proposition: Lemma valid_sepI (x y : U) : valid (x \+ y) -> valid (pval x \+ pval y) && D (pval x) (pval y).
proof: Proof. by rewrite valid_sep. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(eqtype fintype) pcm(options axioms prelude) pcm(pcm)