There are at least two statements known as Schur's lemma.
1. The endomorphism ring of an irreducible module is a division algebra.
2. Let , be irreducible (linear) G-spaces and a G-linear map. Then is either invertible or (Hsiang 2000, p. 3).
There are at least two statements known as Schur's lemma.
1. The endomorphism ring of an irreducible module is a division algebra.
2. Let , be irreducible (linear) G-spaces and a G-linear map. Then is either invertible or (Hsiang 2000, p. 3).
Weisstein, Eric W. "Schur's Lemma." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SchursLemma.html