proposition: Lemma component_connected A x : connected (connected_component A x).
proof: Proof. by apply: bigcup_connected; [exists x => C []|move=> C []]. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed