proposition: Fact lfun_addA : associative add_lfun.
proof: Proof. by move=> f g h; apply/lfunP=> v; rewrite !lfunE /= !lfunE addrA. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)