fact: Definition ex_lim_base {X : UU} {T : TopologicalSpace} (f : X → T) (F : Filter X) := ∃ (x : T) base, is_lim_base f F x base.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.Topology.Filters UniMath.Algebra.Groups UniMath.Algebra.DivisionRig UniMath.Algebra.ConstructiveStructures