fact: Definition initial_segment `{PropResizing} {A : Type} {R : Lt A} `{IsOrdinal A R} (a : A) : Ordinal.
imports: HoTT(TruncType ExcludedMiddle Modalities.ReflectiveSubuniverse abstract_algebra) HoTT(PropResizing.PropResizing) HoTT(Colimits.Quotient) HoTT(HSet)