proposition: Lemma fcvg_ball {F} {FF : Filter F} (y : M) : F --> y -> forall eps : R, 0 < eps -> \forall y' \near F, ball y eps y'.
proof: Proof. by move/fcvg_ballP. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed