fact: Fixpoint filterI_iter {T : Type} (F : set (set T)) (n : nat) := if n is m.+1 then [set P `&` Q | P in filterI_iter F m & Q in filterI_iter F m] else setT |` F.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed