proposition: Lemma prl_same_dataT S S' S'' : prl_same_data S S' -> prl_same_data S' S'' -> prl_same_data S S''.
proof: Proof. by rewrite /prl_same_data; move => [-> -> ->]. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)