fact: Fixpoint rel {gT} (e : seq gT) f r := match f with | Eq2 s t => and_rel (eval e s) (eval e t) r | And f1 f2 => rel e f1 (rel e f2 r) end.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq) mathcomp(fintype finset fingroup morphism)