proposition: Lemma entourage_from_ballE {R : numDomainType} {M : pseudoMetricType R} : @filter_from R _ [set x : R | 0 < x] (fun e => [set xy | @ball R M xy.1 e xy.2]) = entourage.
proof: Proof. by rewrite -entourage_ballE. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed