proposition: Lemma filterE {T : Type} {F : set_system T} : Filter F -> forall P : set T, (forall x, P x) -> F P.
proof: Proof. by move=> [FT _ +] P fP => /(_ setT); apply. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed