proposition: Lemma Wedderburn_sum : (\sum_i 'R_i :=: R_G)%MS.
proof: Proof. by apply: eqmx_trans sums_R _; rewrite /Socle irr_mx_sum mul1mx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop prime) mathcomp(ssralg poly polydiv finset fingroup morphism) mathcomp(perm automorphism quotient finalg action zmodp) mathcomp(commutator cyclic center pgroup matrix mxalgebra) mathcomp(mxpoly)