fact: Definition Book_3_3_solution_1 (A : Type) (B : A -> Type) := @HoTT.Types.Sigma.istrunc_sigma A B 0.
imports: HoTT(Basics Types HProp HSet Projective TruncType Truncations Modalities.Notnot Modalities.Open Modalities.Closed BoundedSearch Equiv.BiInv Spaces.Nat Spaces.Torus.TorusEquivCircles Metatheory.Core Metatheory.FunextVarieties)