proposition: Fact addq_subdefA : associative addq_subdef.
proof: Proof. move=> x y z; rewrite !addq_subdefE. by rewrite !mulrA !mulrDl addrA ![_ * x.2]mulrC !mulrA. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg countalg div ssrnum) mathcomp(ssrint prime archimedean)