- #1

HDB1

- 77

- 7

**Schur's Lemma**;

Let $\phi: L \rightarrow g I((V)$ be irreducible. Then the only endomorphisms of $V$ commuting with all $\phi(x)(x \in L)$ are the scalars.

Could you explain it, and please, how we can apply this lemma on lie algebra ##L=\mathfrak{s l}(2)##

**thanks in advance,**