fact: Definition eisretr_path_sum {A B} {z z' : A + B} : (path_sum z z') o (@path_sum_inv _ _ z z') == idmap := fun p => match p as p in (_ = z') return path_sum z z' (path_sum_inv p) = p with | 1 => match z as z return path_sum z z (path_sum_inv 1) = 1 with | inl _ => 1 | inr _ => 1 end end.
imports: HoTT.Basics Types.Empty Types.Unit Types.Prod Types.Sigma Types.Bool Types.Forall