Pretriangulated dg categories

The internal dg data of zero objects, shifts, and cones, together with the intrinsic triangulated theory of H⁰ it induces (Pretriangulated/H0/).

Comparison with a specified triangulated category -- an equivalence, and the shift and exactness compatibilities that make it an enhancement -- is owned by DerivedAlgGeo.CategoryTheory.Triangulated.DGEnhancement, and the homotopy- category realization by DerivedAlgGeo.Algebra.Homology.HomotopyCategory.DGEnhancement. Both import this root; neither is imported by it.