Marginal cost: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
No edit summary
 
en>Excirial
m Reverted edits by 2602:306:CEDA:2770:E07D:CF87:5A5F:80D identified as vandalism (HG 3)
Line 1: Line 1:
Planet is driven by availability plus demand. Many shall examine the Greek-Roman model. Consuming special care to highlight the component of clash of clans hack tool no survey within the vast building which usually this will provide.<br><br>Returning to conclude, clash of clans hack tool no survey must not be available to get in during of the bigger question: what makes we here? Putting this particular away its of great skilled dallas pest control. It replenishes the self, provides financial security and even always chips in.<br><br>To take pleasure from unlimited points, resources, loose change or gems, you needs to download the clash of clans identify tool by clicking in the button. Depending regarding the operating system that are generally using, you will need to run the downloaded doc as administrator. Provide the log in ID and select the device. Immediately this, you are would be wise to enter the number behind gems or coins you require to get.<br><br>Where you're playing a gameplay online, and you run across another player in which seems to be increasing other players (or you, in particular) intentionally, cannot take it personally. This is called "Griefing," and it's the video game equivalent of [http://Www.dailymail.co.uk/home/search.html?sel=site&searchPhrase=Internet+trolling Internet trolling]. Griefers are you can just out for negative attention, and you give them all what they're looking with regard to if you interact all of them. Don't get emotionally spent in what's happening in addition to simply try to ignore it.<br><br>You should definitely may not let on-line computer games take over your daily life. Game titles can be quite additive, and also have have to make indeed you moderate the a period of time that you investing collaborating in such games. If you invest an excessive amount of time playing video game, your actual life could begin to falter.<br><br>A person are the proud possessor of an ANY easily portable device that runs on iOS or android as a touchscreen tablet equipment or a smart phone, then you definitely would need to have already been very careful of the revolution taking in place right now within the world of mobile computer game "The Clash Associated with Clans", and you would be likely to be in demand of conflict of families unfastened jewels [http://www.Wikipedia.org/wiki/compromise compromise] because lots more gems, elixir and senior are needed seriously to finally acquire every battle.<br><br>A lot of them are not really cheats, they are excuses. The odds are extremely good that unless you include dating a certain commercial golfer or a are insane star along the possibility this is not probably gonna happen to you. When you loved this informative article and you would like to receive details concerning [http://prometeu.net clash of Clans Hack no download no survey] i implore you to visit our own web-page. In John 4:23 as well 24 Jesus tells our website we are to worship God "in spirit whereas in truth. Once entered, the Ruzzle cheat will likely then show a list of all of the possible words that can be accomplished. Using a PSP Market Emulator is a easy way to hack your PSP and open together new worlds of merriment. s these university students played Casino poker and other casino game titles simply for fun.
In [[mathematics]], a '''Hopf algebra''', named after [[Heinz Hopf]], is a structure that is simultaneously an ([[unital algebra|unital]] associative) [[Associative algebra|algebra]] and a (counital coassociative) [[coalgebra]], with these structures' compatibility making it a [[bialgebra]], and that moreover is equipped with an [[antiautomorphism]] satisfying a certain property. The [[representation theory]] of a Hopf algebra is particularly nice, since the existence of compatible comultiplication, counit, and antipode allows for the construction of tensor products of representations, trivial representations, and dual representations.
 
Hopf algebras occur naturally in [[algebraic topology]], where they originated and are related to the [[H-space]] concept, in [[group scheme]] theory, in [[group theory]] (via the concept of a [[group ring]]), and in numerous other places, making them probably the most familiar type of [[bialgebra]]. Hopf algebras are also studied in their own right, with much work on specific classes of examples on the one hand and classification problems on the other.
 
==Formal definition==
Formally, a Hopf algebra is a (associative and coassociative) [[bialgebra]] ''H'' over a [[field (mathematics)|field]] ''K'' together with a [[linear transformation|''K''-linear]] map ''S'': ''H'' → ''H'' (called the '''antipode''') such that the following diagram [[commutative diagram|commutes]]:
<div style="text-align: center;">
[[Image:Hopf algebra.svg|250px|antipode commutative diagram]]
</div>
Here Δ is the comultiplication of the bialgebra, ∇ its multiplication, η its unit and ε its counit. In the sumless [[Sweedler notation]], this property can also be expressed as
:<math>S(c_{(1)})c_{(2)}=c_{(1)}S(c_{(2)})=\epsilon(c)1\qquad\mbox{ for all }c\in H.</math>
 
As for [[associative algebra|algebra]]s, one can replace the underlying field ''K'' with a [[commutative ring]] ''R'' in the above definition.<ref name=Und55>Underwood (2011) p.55</ref>
 
The definition of Hopf algebra is [[Dual (category theory)|self-dual]] (as reflected in the symmetry of the above diagram), so if one can define a [[Dual space|dual]] of ''H'' (which is always possible if ''H'' is finite-dimensional), then it is automatically a Hopf algebra.<ref name=Und62>Underwood (2011) p.62</ref>
 
===Properties of the antipode===
The antipode ''S'' is sometimes required to have a ''K''-linear inverse, which is automatic in the finite-dimensional case, or if ''H'' is [[commutative]] or [[cocommutative]] (or more generally [[Quasitriangular Hopf algebra|quasitriangular]]).
 
In general, ''S'' is an [[antihomomorphism]],<ref>Dăscălescu, Năstăsescu & Raianu (2001), Prop. 4.2.6, {{Google books quote|id=pBJ6sbPHA0IC|page=153|text=is an antimorphism of algebras|p. 153}}</ref> so ''S''<sup>2</sup> is a [[homomorphism]], which is therefore an automorphism if ''S'' was invertible (as may be required).
 
If ''S''<sup>2</sup> = id<sub>''H''</sub>, then the Hopf algebra is said to be '''involutive''' (and the underlying algebra with involution is a [[*-algebra]]). If ''H'' is finite-dimensional semisimple over a field of characteristic zero, commutative, or cocommutative, then it is involutive.
 
If a bialgebra ''B'' admits an antipode ''S'', then ''S'' is unique ("a bialgebra admits at most 1 Hopf algebra structure").<ref>Dăscălescu, Năstăsescu & Raianu (2001), Remarks 4.2.3, {{Google books quote|id=pBJ6sbPHA0IC|page=151|text=the antipode is unique|p. 151}}</ref>
 
The antipode is an analog to the inversion map on a group that sends ''g'' to ''g''<sup>−1</sup>.<ref>[http://www.mathematik.uni-muenchen.de/~pareigis/Vorlesungen/98SS/Quantum_Groups/LN2_1.PDF Quantum groups lecture notes]</ref>
 
===Hopf subalgebras===
A subalgebra ''A'' of a Hopf algebra ''H'' is a Hopf subalgebra if it is a subcoalgebra of ''H'' and the antipode ''S'' maps ''A'' into ''A''. In other words, a Hopf subalgebra A is a Hopf algebra in its own right when the multiplication, comultiplication, counit and antipode of ''H'' is restricted to ''A'' (and additionally the identity 1 of ''H'' is  required to be in A). The Nichols-Zoeller Freeness theorem  established (in 1989) that the natural ''A''-module ''H'' is free of finite rank if ''H'' is finite dimensional: a generalization of [[Lagrange's theorem (group theory)|Lagrange's theorem for subgroups]].  As a corollary of this and integral theory, a Hopf subalgebra of a semisimple finite-dimensional Hopf algebra is automatically semisimple.   
 
A Hopf subalgebra ''A'' is said to be right normal in a Hopf algebra ''H'' if it satisfies the condition of stability, ''ad<sub>r</sub>''(''h'')(''A'') ⊆ ''A'' for all ''h'' in ''H'', where the right adjoint mapping ''ad<sub>r</sub>'' is defined by ''ad<sub>r</sub>''(''h'')(''a'') = ''S''(''h''<sub>(1)</sub>)''ah''<sub>(2)</sub> for all ''a'' in ''A'', ''h'' in ''H''.  Similarly, a Hopf subalgebra ''A'' is left normal in ''H'' if it is stable under the left adjoint mapping defined by ''ad<sub>l</sub>''(''h'')(''a'') = ''h''<sub>(1)</sub>''aS''(''h''<sub>(2)</sub>).  The two conditions of normality are equivalent if the antipode ''S'' is bijective, in which case ''A'' is said to be a normal Hopf subalgebra.
 
A normal Hopf subalgebra ''A'' in ''H'' satisfies the condition (of equality of subsets of H): ''HA''<sup>+</sup> = ''A''<sup>+</sup>''H'' where ''A''<sup>+</sup> denotes the kernel of the counit on ''K''. This normality condition implies that ''HA''<sup>+</sup> is a Hopf ideal of ''H'' (i.e. an algebra ideal in the kernel of the counit, a coalgebra coideal and stable under the antipode).  As a consequence one has a quotient Hopf algebra ''H''/''HA''<sup>+</sup> and epimorphism ''H'' → ''H''/''A''<sup>+</sup>''H'', a theory analogous to that of normal subgroups and quotient groups in [[group theory]].<ref>Montgomery (1993) p.36</ref>
 
===Hopf orders===
A '''Hopf order''' ''O'' over an [[integral domain]] ''R'' with [[field of fractions]] ''K'' is an [[Order (ring theory)|order]] in a Hopf algebra ''H'' over ''K'' which is closed under the algebra and coalgebra operations: in particular, the comultiplication Δ maps ''O'' to ''O''⊗''O''.<ref name=Und82>Underwood (2011) p.82</ref>
 
==Representation Theory==
Let ''A'' be a Hopf algebra, and let ''M'' and ''N'' be ''A''-modules. Then, ''M'' ⊗ ''N'' is also an ''A''-module, with
:<math>a(m\otimes n):=\Delta(a)(m \otimes n)=(a_1\otimes a_2)(m\otimes n)=(a_1 m \otimes a_2 n)</math>
for ''m'' ∈ ''M'', ''n'' ∈ ''N'' and Δ(''a'') = (''a''<sub>1</sub>, ''a''<sub>2</sub>). Furthermore, we can define the trivial representation as the base field ''K'' with
:<math>a(m):=\epsilon(a)m</math>
for ''m'' ∈ ''K''. Finally, the dual representation of ''A'' can be defined: if ''M'' is an ''A''-module and ''M*'' is its dual space, then
:<math>(af)(m):=f(S(a)m)</math>
where ''f'' ∈ ''M*'' and ''m'' ∈ ''M''.
 
The relationship between Δ, ε, and ''S'' ensure that certain natural homomorphisms of vector spaces are indeed homomorphisms of ''A''-modules. For instance, the natural isomorphisms of vector spaces ''M'' → ''M'' ⊗ ''K'' and ''M'' → ''K'' ⊗ ''M'' are also isomorphisms of ''A''-modules. Also, the map of vector spaces ''M*'' ⊗ ''M'' → ''K'' with ''f'' ⊗ ''m'' → ''f''(''m'') is also a homomorphism of ''A''-modules. However, the map ''M'' ⊗ ''M*'' → ''K'' is not necessarily a homomorphism of ''A''-modules.
 
== Examples ==
{| class="wikitable"
|-
!  !! Depending on !! Comultiplication !! Counit !! Antipode !! Commutative !! Cocommutative !! Remarks
|-
| [[group ring|group algebra]] ''KG''  || [[group (mathematics)|group]] ''G''  || Δ(''g'') = ''g'' ⊗ ''g'' for all ''g'' in ''G'' || ε(''g'') = 1 for all ''g'' in ''G'' || ''S''(''g'') = ''g''<sup>−1</sup> for all ''g'' in ''G'' || if and only if ''G'' is abelian || yes ||
|-
| functions ''f'' from a finite<ref>The finiteness of ''G'' implies that ''K<sup>G</sup>'' ⊗ ''K<sup>G</sup>'' is naturally isomorphic to ''K''<sup>''G''x''G''</sup>. This is used in the above formula for the comultiplication. For infinite groups ''G'', ''K<sup>G</sup>'' ⊗ ''K<sup>G</sup>'' is a proper subset of ''K''<sup>''G''x''G''</sup>. In this case the space of functions with finite [[support (mathematics)|support]] can be endowed with a Hopf algebra structure.</ref> group to ''K'', ''K<sup>G</sup>'' (with pointwise addition and multiplication) || finite group ''G'' || Δ(''f'')(''x'',''y'') = ''f''(''xy'') || ε(''f'') = ''f''(1<sub>''G''</sub>)|| ''S''(''f'')(''x'') = ''f''(''x''<sup>−1</sup>)  || yes || if and only if ''G'' is commutative ||
|-
|[[Representative function]]s on a compact group||compact group ''G'' || Δ(''f'')(''x'',''y'') = ''f''(''xy'') || ε(''f'') = ''f''(1<sub>''G''</sub>)|| ''S''(''f'')(''x'') = ''f''(''x''<sup>−1</sup>)  || yes || if and only if ''G'' is commutative || Conversely, every commutative involutive [[reduced algebra|reduced]] Hopf algebra over '''C''' with a finite Haar integral arises in this way, giving one formulation of [[Tannaka–Krein duality]].<ref>{{citation|last=Hochschild|first=G|title=Structure of Lie groups|year=1965|pages=14-32|publisher=Holden-Day}}</ref>
|-
| [[Regular function]]s on an [[algebraic group]] || || Δ(''f'')(''x'',''y'') = ''f''(''xy'') || ε(''f'') = ''f''(1<sub>''G''</sub>)|| ''S''(''f'')(''x'') = ''f''(''x''<sup>−1</sup>)  || yes || if and only if ''G'' is commutative || Conversely, every commutative Hopf algebra over a field arises from a [[group scheme]] in this way, giving an [[equivalence (category theory)|antiequivalence]] of categories.<ref>{{Citation | last1=Jantzen | first1=Jens Carsten | author1-link=Jens Carsten Jantzen | title=Representations of algebraic groups | publisher=[[American Mathematical Society]] | location=Providence, R.I. | edition=2nd | series=Mathematical Surveys and Monographs | isbn=978-0-8218-3527-2 | year=2003 | volume=107}}, section 2.3</ref>
|-
| [[Tensor algebra]] T(''V'') || [[vector space]] ''V'' || Δ(''x'') = ''x'' ⊗ 1 + 1 ⊗ ''x'', ''x'' in ''V'' || ε(''x'') = 0  || ''S''(''x'') = −''x'' for all ''x'' in ''T<sup>1</sup>(V)'' (and extended to higher tensor powers) || no || yes || [[symmetric algebra]] and [[exterior algebra]] (which are quotients of the tensor algebra) are also Hopf algebras with this definition of the comultiplication, counit and antipode
|-
| [[Universal enveloping algebra]] U(g) || [[Lie algebra]] ''g'' || Δ(''x'') = ''x'' ⊗ 1 + 1 ⊗ ''x'' for every ''x'' in ''g'' (this rule is compatible with [[commutator]]s and can therefore be uniquely extended to all of ''U'') || ε(''x'') = 0 for all ''x'' in ''g'' (again, extended to ''U'') || ''S''(''x'') = −''x''  || no || yes ||
|-
| [[Sweedler's Hopf algebra]] ''H''=''K''[''c'', ''x'']/''c<sup>2</sup>'' = 1, ''x''<sup>2</sup> = 0 and ''xc'' = −''cx''.|| ''K'' is a field with [[Field characteristic|characteristic]] different from 2 || Δ(''c'') = ''c'' ⊗ ''c'',  Δ(''x'') = ''c'' ⊗ ''x'' + ''x'' ⊗ 1, Δ(1) = 1 ⊗ 1 || ε(''c'') = 1 and ε(''x'') = 0 || ''S''(''c'') = ''c<sup>−1</sup> = c'' and ''S(x)'' = −''cx'' || no || no || The underlying [[vector space]] is generated by ''{1, c, x, cx}'' and thus has dimension 4. This is the smallest example of a Hopf algebra that is both non-commutative and non-cocommutative.
|}
 
Note that functions on a finite group can be identified with the group ring, though these are more naturally thought of as dual – the group ring consists of ''finite'' sums of elements, and thus pairs with functions on the group by evaluating the function on the summed elements.
 
== Cohomology of Lie groups ==
The cohomology algebra of a Lie group is a Hopf algebra: the multiplication is provided by the cup-product, and the comultiplication
:<math>H^*(G) \rightarrow H^*(G\times G) \cong H^*(G)\otimes H^*(G)</math>
by the group multiplication ''G'' × ''G'' → ''G''. This observation was actually a source of the notion of Hopf algebra. Using this structure, Hopf proved a structure theorem for the cohomology algebra of Lie groups.
 
'''Theorem (Hopf)'''<ref>Hopf, 1941.</ref> Let ''A'' be a finite-dimensional, [[Graded-commutative|graded commutative]], graded cocommutative Hopf algebra over a field of characteristic 0. Then ''A'' (as an algebra) is a free exterior algebra with generators of odd degree.
 
==Quantum groups and non-commutative geometry==
{{Main|quantum group}}
 
All examples above are either commutative (i.e. the multiplication is [[commutative]]) or co-commutative (i.e.<ref name=Und57>Underwood (2011) p.57</ref> Δ = ''T'' ∘ Δ where the ''twist map''<ref name=Und36>Underwood (2011) p.36</ref> ''T'': ''H'' ⊗ ''H'' → ''H'' ⊗ ''H'' is defined by ''T''(''x'' ⊗ ''y'') = ''y'' ⊗ ''x'').  Other interesting Hopf algebras are certain "deformations" or "[[quantization (physics)|quantization]]s" of those from example 3 which are neither commutative nor co-commutative. These Hopf algebras are often called ''[[quantum groups]]'', a term that is so far only loosely defined. They are important in [[noncommutative geometry]], the idea being the following: a standard algebraic group is well described by its standard Hopf algebra of regular functions; we can then think of the deformed version of this Hopf algebra as describing a certain "non-standard" or "quantized" algebraic group (which is not an algebraic group at all). While there does not seem to be a direct way to define or manipulate these non-standard objects, one can still work with their Hopf algebras, and indeed one ''identifies'' them with their Hopf algebras. Hence the name "quantum group".
 
== Related concepts ==
[[Graded algebra|Graded]] Hopf algebras are often used in [[algebraic topology]]: they are the natural algebraic structure on the direct sum of all [[homology (mathematics)|homology]] or [[cohomology]] groups of an [[H-space]].
 
[[Locally compact quantum group]]s generalize Hopf algebras and carry a [[topological space|topology]]. The algebra of all [[continuous function]]s on a [[Lie group]] is a locally compact quantum group.
 
[[Quasi-Hopf algebra]]s are generalizations of Hopf algebras, where coassociativity only holds up to a twist.  They have been used in the study of the [[Knizhnik–Zamolodchikov equations]].<ref name=Mon203>Montgomery (1993) p.203</ref>
 
[[Multiplier Hopf algebra]]s introduced by Alfons Van Daele in 1994<ref>Alfons Van Daele. ''[http://www.ams.org/tran/1994-342-02/S0002-9947-1994-1220906-5/S0002-9947-1994-1220906-5.pdf Multiplier Hopf algebras]'', Transactions of the American Mathematical Society 342(2) (1994) 917-932</ref> are generalizations of [[Hopf algebras]] where comultiplication from an algebra (with or withthout unit) to the [[multiplier algebra]] of tensor product algebra of the algebra with itself.
 
[[Hopf group-(co)algebra]]s introduced by V.G.Turaev in 2000 are also generalizations of Hopf algebras.
 
===Weak Hopf Algebras===
[[Weak Hopf algebra]]s, or quantum groupoids, are  generalizations of Hopf algebras. Like Hopf algebras, weak Hopf algebras form a self-dual class of algebras; i.e., if ''H'' is a (weak) Hopf algebra, so is ''H*'', the dual space of linear forms on ''H'' (with respect to the algebra-coalgebra structure obtained from  the natural pairing with ''H'' and its coalgebra-algebra structure). A weak Hopf algebra ''H'' is usually taken to be a
 
*finite dimensional algebra and coalgebra with coproduct Δ: ''H'' → ''H'' ⊗ ''H''  and counit ε: ''H'' → ''k'' satisfying all the axioms of Hopf algebra except possibly Δ(1) ≠ 1 ⊗ 1 or ε(''ab'') ≠ ε(''a'')ε(''b'') for some ''a,b'' in ''H''.  Instead one requires the following:
 
::<math> (\Delta(1) \otimes 1)(1 \otimes \Delta(1)) = (1 \otimes \Delta(1))(\Delta(1) \otimes 1) = (\Delta \otimes \mbox{Id})\Delta(1)</math>
::<math> \epsilon(abc) = \sum \epsilon(ab_{(1)})\epsilon(b_{(2)}c) = \sum \epsilon(ab_{(2)})\epsilon(b_{(1)}c)</math>
 
:for all ''a'', ''b'', and ''c'' in ''H''.
 
* ''H'' has a weakened antipode ''S'': ''H'' → ''H'' satisfying the axioms:
 
#<math>S(a_{(1)})a_{(2)} = 1_{(1)} \epsilon(a 1_{(2)})</math> for all ''a'' in ''H'' (the right-hand side is the interesting projection usually denoted by Π<sup>''R''</sup>(''a'') or ε<sub>''s''</sub>(''a'') with image a separable subalgebra denoted by ''H<sup>R</sup>'' or ''H<sub>s</sub>'');
#<math>a_{(1)}S(a_{(2)}) =  \epsilon(1_{(1)}a)1_{(2)}</math> for all ''a'' in ''H'' (another interesting projection usually denoted by Π<sup>''R''</sup>(''a'') or ε<sub>''t''</sub>(''a'') with image a separable algebra ''H<sup>L</sup>'' or ''H<sub>t</sub>'', anti-isomorphic to ''H<sup>L</sup>'' via ''S'');
#<math>S(a_{(1)})a_{(2)}S(a_{(3)}) = S(a) </math> for all ''a'' in ''H''. 
 
:Note that if Δ(1) = 1 ⊗ 1, these conditions reduce to the two usual conditions on the antipode of a Hopf algebra.
 
The axioms are partly chosen so that the category of ''H''-modules is a [[rigid category|rigid monoidal category]]. The unit ''H''-module is the separable algebra ''H<sup>L</sup>'' mentioned above. 
For example, a finite [[groupoid]] algebra is a weak Hopf algebra.  In particular, the groupoid algebra on [n] with one pair of invertible arrows ''e<sub>ij</sub>'' and ''e<sub>ji</sub>''  between ''i'' and ''j'' in [''n''] is isomorphic to the algebra ''H'' of ''n'' x ''n'' matrices. The weak Hopf algebra structure on this particular ''H'' is given by coproduct Δ(''e<sub>ij</sub>'') = ''e<sub>ij</sub>'' ⊗ ''e<sub>ij</sub>'', counit ε(''e<sub>ij</sub>'') = 1 and antipode ''S''(''e<sub>ij</sub>'') = ''e<sub>ji</sub>''. The separable subalgebras ''H<sup>L</sup>'' and ''H<sup>R</sup>'' coincide and are non-central commutative algebras in this particular case (the subalgebra of diagonal matrices).   
 
Early theoretical contributions to weak Hopf algebras are to be found in <ref>Gabriella Böhm,  Florian Nill, Kornel Szlachanyi. J. Algebra 221 (1999), 385-438</ref> as well as <ref>Dmitri Nikshych, Leonid Vainerman, in: New direction in Hopf algebras, S. Montgomery and H.-J. Schneider, eds., M.S.R.I. Publications, vol. 43, Cambridge, 2002, 211-262.</ref>   
 
===Hopf Algebroids===
[[Hopf algebroid]]s introduced by J.-H. Lu in 1996 as a result on work on groupoids in Poisson geometry (later shown equivalent in nontrivial way to a construction of Takeuchi from the 1970s and another by Xu around the year 2000): Hopf algebroids generalize weak Hopf algebras and certain skew Hopf algebras. They may be loosely thought of as Hopf algebras over a noncommutative base ring, where weak Hopf algebras become Hopf algebras over a separable algebra.  It is a theorem that a Hopf algebroid satisfying a finite projectivity condition over a separable algebra is a weak Hopf algebra, and conversely a weak Hopf algebra ''H'' is a Hopf algebroid over its separable subalgebra ''H<sup>L</sup>''. The antipode axioms have been changed by G. Böhm and K. Szlachanyi (J. Algebra) in 2004 for tensor categorical reasons and to accommodate examples associated to depth two [[Frobenius algebra]] extensions.
 
A left Hopf algebroid (''H'', ''R'')  is a left bialgebroid together with an antipode: the bialgebroid (''H'', ''R'') consists of a total algebra ''H'' and a base algebra ''R'' and two mappings, an algebra homomorphism ''s'': ''R'' → ''H'' called a source map, an algebra anti-homomorphism ''t'': ''R'' → ''H'' called a target map, such that the commutativity condition ''s''(''r''<sub>1</sub>) ''t''(''r''<sub>2</sub>) = ''t''(''r''<sub>2</sub>) ''s''(''r''<sub>1</sub>) is satisfied for all ''r''<sub>1</sub>, ''r''<sub>2</sub> ∈ ''R''.  The axioms resemble those of a Hopf algebra but  are complicated by the possibility that ''R'' is a non-commutative algebra or its images under ''s'' and ''t'' are not in the center of ''H''. In particular a left bialgebroid (''H'', ''R'')  has an ''R''-''R''-bimodule structure on ''H'' which prefers the left side as follows:  ''r''<sub>1</sub> ⋅ ''h'' ⋅ ''r''<sub>2</sub> = ''s''(''r''<sub>1</sub>) ''t''(''r''<sub>2</sub>) ''h'' for all ''h'' in ''H'', ''r''<sub>1</sub>, ''r''<sub>2</sub> ∈ ''R''.  There is a coproduct Δ: ''H'' → ''H'' ⊗<sub>''R''</sub> ''H'' and counit ε: ''H'' → ''R''  that make (''H'', ''R'', Δ, ε) an ''R''-coring (with axioms like that of a [[coalgebra]] such that all mappings are ''R''-''R''-bimodule homomorphisms and all tensors over ''R'').  Additionally the bialgebroid (''H'', ''R'') must satisfy Δ(''ab'') = Δ(''a'')Δ(''b'') for all ''a'', ''b'' in ''H'', and a condition to make sure this last condition makes sense:  every image point Δ(''a'') satisfies ''a''<sub>(1)</sub> ''t''(''r'') ⊗ ''a''<sub>(2)</sub> =  ''a''<sub>(1)</sub> ⊗ ''a''<sub>(2)</sub> ''s''(''r'') for all ''r'' in ''R''. Also Δ(1) = 1 ⊗ 1.  The counit is required to satisfy ε(1<sub>''H''</sub>) = 1<sub>''R''</sub> and the condition ε(''ab'') = ε(''as''(ε(''b''))) = ε(''at''(ε(''b''))).
 
The antipode ''S'': ''H'' → ''H'' is usually taken to be an algebra anti-automorphism satisfying conditions of exchanging the source and target maps and satisfying two axioms like Hopf algebra antipode axioms;  see the references in Lu or in Böhm-Szlachanyi for a more example-category friendly, though somewhat more complicated, set of axioms for the antipode ''S''.  The latter set of  axioms depend on the axioms of a right bialgebroid as well, which are a straightforward switching of left to right, ''s'' with ''t'', of the axioms for a left bialgebroid given above. 
 
As an example of left bialgebroid, take ''R'' to be any algebra over a field ''k''.  Let ''H'' be its algebra of linear self-mappings. Let s(r) be left multiplication by ''r'' on ''R''; let ''t''(''r'') be right multiplication by ''r'' on ''R''.  ''H'' is a left bialgebroid over ''R'', which may be seen as follows.  From the fact that ''H'' ⊗<sub>''R''</sub> ''H'' ≅ Hom<sub>''k''</sub>(''R'' ⊗ ''R'', ''R'') one may define a coproduct by Δ(''f'')(''r'' ⊗ ''u'') = ''f''(''ru'') for each linear transformation ''f'' from ''R'' to itself and all ''r'', ''u'' in ''R''. Coassociativity of the coproduct follows from associativity of the product on R.  A counit  is given by ε(''f'') = ''f''(1). The counit axioms of a coring follow from the identity element condition on multiplication in ''R''. The reader will be amused, or at least edified, to check that (''H'', ''R'') is a left bialgebroid.  In case ''R'' is an Azumaya algebra, in which case ''H'' is isomorphic to ''R'' ⊗ ''R'', an antipode comes from transposing tensors, which makes ''H'' a Hopf algebroid over ''R''.
 
==Analogy with groups==
Groups can be axiomatized by the same diagrams (equivalently, operations) as a Hopf algebra, where ''G'' is taken to be a set instead of a module. In this case:
* the field ''K'' is replaced by the 1-point set
* there is a natural counit (map to 1 point)
* there is a natural comultiplication (the diagonal map)
* the unit is the identity element of the group
* the multiplication is the multiplication in the group
* the antipode is the inverse
In this philosophy, a group can be thought of as a Hopf algebra over the "[[field with one element]]".<ref>[http://sbseminar.wordpress.com/2007/10/07/group-hopf-algebra/ Group = Hopf algebra « Secret Blogging Seminar<!-- Bot generated title -->], [http://www.youtube.com/watch?v=p3kkm5dYH-w Group objects and Hopf algebras], video of Simon Willerton.</ref>
 
== See also ==
* [[Quasitriangular Hopf algebra]]
* [[Algebra/set analogy]]
* [[Representation theory of Hopf algebras]]
* [[Ribbon Hopf algebra]]
* [[Superalgebra]]
* [[Supergroup (physics)|Supergroup]]
* [[Anyonic Lie algebra]]
* [[Sweedler's Hopf algebra]]
 
==Notes and references==
=== Notes ===
{{reflist|1}}
 
=== References ===
* {{Citation| last1=Dăscălescu| first1=Sorin| last2=Năstăsescu| first2=Constantin| last3=Raianu| first3=Șerban| year=2001| title=Hopf Algebras. An introduction| edition=1st| volume = 235| series=Pure and Applied Mathematics | publisher=Marcel Dekker| isbn = 0-8247-0481-9 | zbl=0962.16026 }}.
* Pierre Cartier, [http://preprints.ihes.fr/2006/M/M-06-40.pdf ''A primer of Hopf algebras''], IHES preprint, September 2006, 81 pages
* {{citation | last=Fuchs | first=Jürgen | title=Affine Lie algebras and quantum groups. An introduction with applications in conformal field theory | series=Cambridge Monographs on Mathematical Physics | location=Cambridge | publisher=[[Cambridge University Press]] | year=1992 | isbn=0-521-48412-X | zbl=0925.17031 }}
* H. Hopf, Uber die Topologie der Gruppen-Mannigfaltigkeiten und ihrer Verallgemeinerungen, Ann. of Math. 42 (1941), 22-52. Reprinted in Selecta Heinz Hopf, pp.&nbsp;119–151, Springer, Berlin (1964). {{MathSciNet | id = 4784}}, {{zbl | 1=0025.09303 }}
* {{citation | last=Montgomery | first=Susan | title=Hopf algebras and their actions on rings | series=Regional Conference Series in Mathematics | volume=82 | location=Providence, RI | publisher=[[American Mathematical Society]] | year=1993 | isbn=0-8218-0738-2 | zbl=0793.16029 }}
* {{Citation | last1=Street | first1=Ross | author1-link=Ross Street | title=Quantum groups | publisher=[[Cambridge University Press]] | series=Australian Mathematical Society Lecture Series | volume=19 | year=2007 | isbn=978-0-521-69524-4 | mr=2294803 | zbl=1117.16031 }}.
*{{Citation | last1=Sweedler | first1=Moss E. | title=Hopf algebras | url=http://books.google.com/books?id=8FnvAAAAMAAJ | publisher=W. A. Benjamin, Inc., New York | series=Mathematics Lecture Note Series | year=1969 | mr=0252485 | zbl=0194.32901  }}
* {{citation | last=Underwood | first=Robert G. | title=An introduction to Hopf algebras | location=Berlin | publisher=[[Springer-Verlag]] | year=2011 | isbn=978-0-387-72765-3 | zbl=1234.16022 }}
 
{{DEFAULTSORT:Hopf Algebra}}
[[Category:Hopf algebras| ]]
[[Category:Monoidal categories]]
[[Category:Representation theory]]

Revision as of 22:03, 4 December 2013

In mathematics, a Hopf algebra, named after Heinz Hopf, is a structure that is simultaneously an (unital associative) algebra and a (counital coassociative) coalgebra, with these structures' compatibility making it a bialgebra, and that moreover is equipped with an antiautomorphism satisfying a certain property. The representation theory of a Hopf algebra is particularly nice, since the existence of compatible comultiplication, counit, and antipode allows for the construction of tensor products of representations, trivial representations, and dual representations.

Hopf algebras occur naturally in algebraic topology, where they originated and are related to the H-space concept, in group scheme theory, in group theory (via the concept of a group ring), and in numerous other places, making them probably the most familiar type of bialgebra. Hopf algebras are also studied in their own right, with much work on specific classes of examples on the one hand and classification problems on the other.

Formal definition

Formally, a Hopf algebra is a (associative and coassociative) bialgebra H over a field K together with a K-linear map S: HH (called the antipode) such that the following diagram commutes:

antipode commutative diagram

Here Δ is the comultiplication of the bialgebra, ∇ its multiplication, η its unit and ε its counit. In the sumless Sweedler notation, this property can also be expressed as

As for algebras, one can replace the underlying field K with a commutative ring R in the above definition.[1]

The definition of Hopf algebra is self-dual (as reflected in the symmetry of the above diagram), so if one can define a dual of H (which is always possible if H is finite-dimensional), then it is automatically a Hopf algebra.[2]

Properties of the antipode

The antipode S is sometimes required to have a K-linear inverse, which is automatic in the finite-dimensional case, or if H is commutative or cocommutative (or more generally quasitriangular).

In general, S is an antihomomorphism,[3] so S2 is a homomorphism, which is therefore an automorphism if S was invertible (as may be required).

If S2 = idH, then the Hopf algebra is said to be involutive (and the underlying algebra with involution is a *-algebra). If H is finite-dimensional semisimple over a field of characteristic zero, commutative, or cocommutative, then it is involutive.

If a bialgebra B admits an antipode S, then S is unique ("a bialgebra admits at most 1 Hopf algebra structure").[4]

The antipode is an analog to the inversion map on a group that sends g to g−1.[5]

Hopf subalgebras

A subalgebra A of a Hopf algebra H is a Hopf subalgebra if it is a subcoalgebra of H and the antipode S maps A into A. In other words, a Hopf subalgebra A is a Hopf algebra in its own right when the multiplication, comultiplication, counit and antipode of H is restricted to A (and additionally the identity 1 of H is required to be in A). The Nichols-Zoeller Freeness theorem established (in 1989) that the natural A-module H is free of finite rank if H is finite dimensional: a generalization of Lagrange's theorem for subgroups. As a corollary of this and integral theory, a Hopf subalgebra of a semisimple finite-dimensional Hopf algebra is automatically semisimple.

A Hopf subalgebra A is said to be right normal in a Hopf algebra H if it satisfies the condition of stability, adr(h)(A) ⊆ A for all h in H, where the right adjoint mapping adr is defined by adr(h)(a) = S(h(1))ah(2) for all a in A, h in H. Similarly, a Hopf subalgebra A is left normal in H if it is stable under the left adjoint mapping defined by adl(h)(a) = h(1)aS(h(2)). The two conditions of normality are equivalent if the antipode S is bijective, in which case A is said to be a normal Hopf subalgebra.

A normal Hopf subalgebra A in H satisfies the condition (of equality of subsets of H): HA+ = A+H where A+ denotes the kernel of the counit on K. This normality condition implies that HA+ is a Hopf ideal of H (i.e. an algebra ideal in the kernel of the counit, a coalgebra coideal and stable under the antipode). As a consequence one has a quotient Hopf algebra H/HA+ and epimorphism HH/A+H, a theory analogous to that of normal subgroups and quotient groups in group theory.[6]

Hopf orders

A Hopf order O over an integral domain R with field of fractions K is an order in a Hopf algebra H over K which is closed under the algebra and coalgebra operations: in particular, the comultiplication Δ maps O to OO.[7]

Representation Theory

Let A be a Hopf algebra, and let M and N be A-modules. Then, MN is also an A-module, with

for mM, nN and Δ(a) = (a1, a2). Furthermore, we can define the trivial representation as the base field K with

for mK. Finally, the dual representation of A can be defined: if M is an A-module and M* is its dual space, then

where fM* and mM.

The relationship between Δ, ε, and S ensure that certain natural homomorphisms of vector spaces are indeed homomorphisms of A-modules. For instance, the natural isomorphisms of vector spaces MMK and MKM are also isomorphisms of A-modules. Also, the map of vector spaces M*MK with fmf(m) is also a homomorphism of A-modules. However, the map MM*K is not necessarily a homomorphism of A-modules.

Examples

Depending on Comultiplication Counit Antipode Commutative Cocommutative Remarks
group algebra KG group G Δ(g) = gg for all g in G ε(g) = 1 for all g in G S(g) = g−1 for all g in G if and only if G is abelian yes
functions f from a finite[8] group to K, KG (with pointwise addition and multiplication) finite group G Δ(f)(x,y) = f(xy) ε(f) = f(1G) S(f)(x) = f(x−1) yes if and only if G is commutative
Representative functions on a compact group compact group G Δ(f)(x,y) = f(xy) ε(f) = f(1G) S(f)(x) = f(x−1) yes if and only if G is commutative Conversely, every commutative involutive reduced Hopf algebra over C with a finite Haar integral arises in this way, giving one formulation of Tannaka–Krein duality.[9]
Regular functions on an algebraic group Δ(f)(x,y) = f(xy) ε(f) = f(1G) S(f)(x) = f(x−1) yes if and only if G is commutative Conversely, every commutative Hopf algebra over a field arises from a group scheme in this way, giving an antiequivalence of categories.[10]
Tensor algebra T(V) vector space V Δ(x) = x ⊗ 1 + 1 ⊗ x, x in V ε(x) = 0 S(x) = −x for all x in T1(V) (and extended to higher tensor powers) no yes symmetric algebra and exterior algebra (which are quotients of the tensor algebra) are also Hopf algebras with this definition of the comultiplication, counit and antipode
Universal enveloping algebra U(g) Lie algebra g Δ(x) = x ⊗ 1 + 1 ⊗ x for every x in g (this rule is compatible with commutators and can therefore be uniquely extended to all of U) ε(x) = 0 for all x in g (again, extended to U) S(x) = −x no yes
Sweedler's Hopf algebra H=K[c, x]/c2 = 1, x2 = 0 and xc = −cx. K is a field with characteristic different from 2 Δ(c) = cc, Δ(x) = cx + x ⊗ 1, Δ(1) = 1 ⊗ 1 ε(c) = 1 and ε(x) = 0 S(c) = c−1 = c and S(x) = −cx no no The underlying vector space is generated by {1, c, x, cx} and thus has dimension 4. This is the smallest example of a Hopf algebra that is both non-commutative and non-cocommutative.

Note that functions on a finite group can be identified with the group ring, though these are more naturally thought of as dual – the group ring consists of finite sums of elements, and thus pairs with functions on the group by evaluating the function on the summed elements.

Cohomology of Lie groups

The cohomology algebra of a Lie group is a Hopf algebra: the multiplication is provided by the cup-product, and the comultiplication

by the group multiplication G × GG. This observation was actually a source of the notion of Hopf algebra. Using this structure, Hopf proved a structure theorem for the cohomology algebra of Lie groups.

Theorem (Hopf)[11] Let A be a finite-dimensional, graded commutative, graded cocommutative Hopf algebra over a field of characteristic 0. Then A (as an algebra) is a free exterior algebra with generators of odd degree.

Quantum groups and non-commutative geometry

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church.

All examples above are either commutative (i.e. the multiplication is commutative) or co-commutative (i.e.[12] Δ = T ∘ Δ where the twist map[13] T: HHHH is defined by T(xy) = yx). Other interesting Hopf algebras are certain "deformations" or "quantizations" of those from example 3 which are neither commutative nor co-commutative. These Hopf algebras are often called quantum groups, a term that is so far only loosely defined. They are important in noncommutative geometry, the idea being the following: a standard algebraic group is well described by its standard Hopf algebra of regular functions; we can then think of the deformed version of this Hopf algebra as describing a certain "non-standard" or "quantized" algebraic group (which is not an algebraic group at all). While there does not seem to be a direct way to define or manipulate these non-standard objects, one can still work with their Hopf algebras, and indeed one identifies them with their Hopf algebras. Hence the name "quantum group".

Related concepts

Graded Hopf algebras are often used in algebraic topology: they are the natural algebraic structure on the direct sum of all homology or cohomology groups of an H-space.

Locally compact quantum groups generalize Hopf algebras and carry a topology. The algebra of all continuous functions on a Lie group is a locally compact quantum group.

Quasi-Hopf algebras are generalizations of Hopf algebras, where coassociativity only holds up to a twist. They have been used in the study of the Knizhnik–Zamolodchikov equations.[14]

Multiplier Hopf algebras introduced by Alfons Van Daele in 1994[15] are generalizations of Hopf algebras where comultiplication from an algebra (with or withthout unit) to the multiplier algebra of tensor product algebra of the algebra with itself.

Hopf group-(co)algebras introduced by V.G.Turaev in 2000 are also generalizations of Hopf algebras.

Weak Hopf Algebras

Weak Hopf algebras, or quantum groupoids, are generalizations of Hopf algebras. Like Hopf algebras, weak Hopf algebras form a self-dual class of algebras; i.e., if H is a (weak) Hopf algebra, so is H*, the dual space of linear forms on H (with respect to the algebra-coalgebra structure obtained from the natural pairing with H and its coalgebra-algebra structure). A weak Hopf algebra H is usually taken to be a

  • finite dimensional algebra and coalgebra with coproduct Δ: HHH and counit ε: Hk satisfying all the axioms of Hopf algebra except possibly Δ(1) ≠ 1 ⊗ 1 or ε(ab) ≠ ε(a)ε(b) for some a,b in H. Instead one requires the following:
for all a, b, and c in H.
  • H has a weakened antipode S: HH satisfying the axioms:
  1. for all a in H (the right-hand side is the interesting projection usually denoted by ΠR(a) or εs(a) with image a separable subalgebra denoted by HR or Hs);
  2. for all a in H (another interesting projection usually denoted by ΠR(a) or εt(a) with image a separable algebra HL or Ht, anti-isomorphic to HL via S);
  3. for all a in H.
Note that if Δ(1) = 1 ⊗ 1, these conditions reduce to the two usual conditions on the antipode of a Hopf algebra.

The axioms are partly chosen so that the category of H-modules is a rigid monoidal category. The unit H-module is the separable algebra HL mentioned above.

For example, a finite groupoid algebra is a weak Hopf algebra. In particular, the groupoid algebra on [n] with one pair of invertible arrows eij and eji between i and j in [n] is isomorphic to the algebra H of n x n matrices. The weak Hopf algebra structure on this particular H is given by coproduct Δ(eij) = eijeij, counit ε(eij) = 1 and antipode S(eij) = eji. The separable subalgebras HL and HR coincide and are non-central commutative algebras in this particular case (the subalgebra of diagonal matrices).

Early theoretical contributions to weak Hopf algebras are to be found in [16] as well as [17]

Hopf Algebroids

Hopf algebroids introduced by J.-H. Lu in 1996 as a result on work on groupoids in Poisson geometry (later shown equivalent in nontrivial way to a construction of Takeuchi from the 1970s and another by Xu around the year 2000): Hopf algebroids generalize weak Hopf algebras and certain skew Hopf algebras. They may be loosely thought of as Hopf algebras over a noncommutative base ring, where weak Hopf algebras become Hopf algebras over a separable algebra. It is a theorem that a Hopf algebroid satisfying a finite projectivity condition over a separable algebra is a weak Hopf algebra, and conversely a weak Hopf algebra H is a Hopf algebroid over its separable subalgebra HL. The antipode axioms have been changed by G. Böhm and K. Szlachanyi (J. Algebra) in 2004 for tensor categorical reasons and to accommodate examples associated to depth two Frobenius algebra extensions.

A left Hopf algebroid (H, R) is a left bialgebroid together with an antipode: the bialgebroid (H, R) consists of a total algebra H and a base algebra R and two mappings, an algebra homomorphism s: RH called a source map, an algebra anti-homomorphism t: RH called a target map, such that the commutativity condition s(r1) t(r2) = t(r2) s(r1) is satisfied for all r1, r2R. The axioms resemble those of a Hopf algebra but are complicated by the possibility that R is a non-commutative algebra or its images under s and t are not in the center of H. In particular a left bialgebroid (H, R) has an R-R-bimodule structure on H which prefers the left side as follows: r1hr2 = s(r1) t(r2) h for all h in H, r1, r2R. There is a coproduct Δ: HHR H and counit ε: HR that make (H, R, Δ, ε) an R-coring (with axioms like that of a coalgebra such that all mappings are R-R-bimodule homomorphisms and all tensors over R). Additionally the bialgebroid (H, R) must satisfy Δ(ab) = Δ(a)Δ(b) for all a, b in H, and a condition to make sure this last condition makes sense: every image point Δ(a) satisfies a(1) t(r) ⊗ a(2) = a(1)a(2) s(r) for all r in R. Also Δ(1) = 1 ⊗ 1. The counit is required to satisfy ε(1H) = 1R and the condition ε(ab) = ε(as(ε(b))) = ε(at(ε(b))).

The antipode S: HH is usually taken to be an algebra anti-automorphism satisfying conditions of exchanging the source and target maps and satisfying two axioms like Hopf algebra antipode axioms; see the references in Lu or in Böhm-Szlachanyi for a more example-category friendly, though somewhat more complicated, set of axioms for the antipode S. The latter set of axioms depend on the axioms of a right bialgebroid as well, which are a straightforward switching of left to right, s with t, of the axioms for a left bialgebroid given above.

As an example of left bialgebroid, take R to be any algebra over a field k. Let H be its algebra of linear self-mappings. Let s(r) be left multiplication by r on R; let t(r) be right multiplication by r on R. H is a left bialgebroid over R, which may be seen as follows. From the fact that HR H ≅ Homk(RR, R) one may define a coproduct by Δ(f)(ru) = f(ru) for each linear transformation f from R to itself and all r, u in R. Coassociativity of the coproduct follows from associativity of the product on R. A counit is given by ε(f) = f(1). The counit axioms of a coring follow from the identity element condition on multiplication in R. The reader will be amused, or at least edified, to check that (H, R) is a left bialgebroid. In case R is an Azumaya algebra, in which case H is isomorphic to RR, an antipode comes from transposing tensors, which makes H a Hopf algebroid over R.

Analogy with groups

Groups can be axiomatized by the same diagrams (equivalently, operations) as a Hopf algebra, where G is taken to be a set instead of a module. In this case:

  • the field K is replaced by the 1-point set
  • there is a natural counit (map to 1 point)
  • there is a natural comultiplication (the diagonal map)
  • the unit is the identity element of the group
  • the multiplication is the multiplication in the group
  • the antipode is the inverse

In this philosophy, a group can be thought of as a Hopf algebra over the "field with one element".[18]

See also

Notes and references

Notes

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

References

  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010.
  • Pierre Cartier, A primer of Hopf algebras, IHES preprint, September 2006, 81 pages
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • H. Hopf, Uber die Topologie der Gruppen-Mannigfaltigkeiten und ihrer Verallgemeinerungen, Ann. of Math. 42 (1941), 22-52. Reprinted in Selecta Heinz Hopf, pp. 119–151, Springer, Berlin (1964). Template:MathSciNet, Template:Zbl
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010.
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  1. Underwood (2011) p.55
  2. Underwood (2011) p.62
  3. Dăscălescu, Năstăsescu & Raianu (2001), Prop. 4.2.6, Template:Google books quote
  4. Dăscălescu, Năstăsescu & Raianu (2001), Remarks 4.2.3, Template:Google books quote
  5. Quantum groups lecture notes
  6. Montgomery (1993) p.36
  7. Underwood (2011) p.82
  8. The finiteness of G implies that KGKG is naturally isomorphic to KGxG. This is used in the above formula for the comultiplication. For infinite groups G, KGKG is a proper subset of KGxG. In this case the space of functions with finite support can be endowed with a Hopf algebra structure.
  9. Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  10. Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010, section 2.3
  11. Hopf, 1941.
  12. Underwood (2011) p.57
  13. Underwood (2011) p.36
  14. Montgomery (1993) p.203
  15. Alfons Van Daele. Multiplier Hopf algebras, Transactions of the American Mathematical Society 342(2) (1994) 917-932
  16. Gabriella Böhm, Florian Nill, Kornel Szlachanyi. J. Algebra 221 (1999), 385-438
  17. Dmitri Nikshych, Leonid Vainerman, in: New direction in Hopf algebras, S. Montgomery and H.-J. Schneider, eds., M.S.R.I. Publications, vol. 43, Cambridge, 2002, 211-262.
  18. Group = Hopf algebra « Secret Blogging Seminar, Group objects and Hopf algebras, video of Simon Willerton.