proposition: Lemma big_rmcond_in (I : eqType) (r : seq I) (P : pred I) F : (forall i, i \in r -> ~~ P i -> F i = 1) -> \big[*%M/1]_(i <- r | P i) F i = \big[*%M/1]_(i <- r) F i.
proof: Proof. move=> F_eq1; rewrite big_seq_cond [RHS]big_seq_cond !big_mkcondl big_rmcond//. by move=> i /F_eq1; case: ifP => // _ ->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div fintype tuple finfun)