fact: Definition abses_pullback_trivial_preimage `{Univalence} {A B C : AbGroup} (E : AbSES C B) (F : AbSES (middle E) A) (p : abses_pullback (inclusion E) F $== pt) : AbSES C A.
imports: Basics Types HSet HFiber Limits.Pullback WildCat Pointed.Core Homotopy.ExactSequence Groups.QuotientGroup AbGroups.AbelianGroup AbGroups.AbPullback AbGroups.Biproduct AbSES.Core AbSES.Pullback Modalities.Identity Modalities.Modality Truncations.Core