# Linear Lie algebra

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In algebra, a **linear Lie algebra** is a subalgebra of the Lie algebra consisting of endomorphisms of a vector space *V*. In other words, a linear Lie algebra is the image of a Lie algebra representation.

Any Lie algebra is a linear Lie algebra in the sense that there is always a faithful representation of (in fact, on a finite-dimensional vector space by Ado's theorem if is itself finite-dimensional.)

Let *V* be a finite-dimensional vector space over a field of characteristic zero and a subalgebra of . Then *V* is semisimple as a module over if and only if (i) it is a direct sum of the center and a semisimple ideal and (ii) the elements of the center are diagonalizable (over some extension field).^{[1]}

## Notes

## References

- Jacobson, Nathan,
*Lie algebras*, Republication of the 1962 original. Dover Publications, Inc., New York, 1979. ISBN 0-486-63832-4