proposition: Lemma pfR e (x y : U) : valid (x \+ y) -> S x y -> e \In f y -> e \In f (x \+ y).
proof: Proof. by move=>W H1 H2; rewrite pfjoin //=; apply: InR=>//; rewrite pfV2. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval) pcm(options prelude pred finmap rtc seqext useqord uslice uconsec)