proposition: Lemma odiv0r a : a != 0 -> 0 %/? a = Some 0.
proof: Proof. case: odivrP=> [x|H _]; last by move: (H 0); rewrite mul0r eqxx. by move/eqP; rewrite eq_sym mulf_eq0 orbC; case: eqP => //= _ /eqP->. Qed.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool Arith.Wf_nat) mathcomp(eqtype ssrnat div seq path) mathcomp(ssralg fintype perm tuple choice generic_quotient) mathcomp(matrix bigop zmodp mxalgebra poly) stronglydiscrete