proposition: Lemma ltn_ptr_semiconn : forall x y : ptr, x != y -> ltn_ptr x y || ltn_ptr y x.
proof: Proof. by case=>x [y]; rewrite ptrE /=; case: ltngtP. Qed.
imports: Coq(ssreflect ssrbool ssrfun Eqdep) mathcomp(ssrnat eqtype seq path) pcm(options axioms finmap) pcm(pcm unionmap)