fact: Fixpoint eval {gT} e t : gT := match t with | Cst i => nth 1 e i | Idx => 1 | Inv t1 => (eval e t1)^-1 | Exp t1 n => eval e t1 ^+ n | Mul t1 t2 => eval e t1 * eval e t2 | Conj t1 t2 => eval e t1 ^ eval e t2 | Comm t1 t2 => [~ eval e t1, eval e t2] end.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq) mathcomp(fintype finset fingroup morphism)