fact: Definition cxfib' {A B C : AbGroup} (E : AbSES C B) : AbSES C A -> graph_hfiber (abses_pullback (A:=A) (inclusion E)) pt.
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