proposition: Lemma gring_op_mx b : gring_op (gring_mx aG b) = gring_mx rG b.
proof: Proof. by rewrite -[_ b]mul1mx gring_opJ gring_op1 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)