fact: Definition connected_component (A : set T) (x : T) := \bigcup_(A in [set C : set T | [/\ C x, C `<=` A & connected C]]) A.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed