proposition: Fact addmA_subproof : associative addmor.
proof: Proof. by move=> x y z; apply: val_inj; apply: addrA. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice matrix bigop zmodp mxalgebra poly) ssrcomplements stronglydiscrete coherent edr