fact: Definition initial_segment_property `{PropResizing} {A : Ordinal} {a : A} : forall x : ↓a, out x < a.
imports: HoTT(TruncType ExcludedMiddle Modalities.ReflectiveSubuniverse abstract_algebra) HoTT(PropResizing.PropResizing) HoTT(Colimits.Quotient) HoTT(HSet)