An Illuminating Proof of Schur’s Orthogonality Relations for Group Representations

Issai Schur s orthogonality relations for characters of group representations are surely a mathematical wonder. Unfortunately, the standard proof, even from great expositors like JP Serre and Michael Artin, typically involves a bunch of index gymnastics that never meant much to me. Back when I was a mathematician, I saw a great proof (for compact Lie Continue reading "An Illuminating Proof of…