fact: Definition filter_prod {T U : Type} (F : set_system T) (G : set_system U) : set_system (T * U) := filter_from (fun P => F P.1 /\ G P.2) (fun P => P.1 `*` P.2).
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed