Commit 2024-10-17 15:41 d9aad453
View on Github →feat(CategoryTheory/Shift): shifted morphisms in the opposite category (#17546)
When C is a triangulated category, we introduce a bijection ShiftedHom.opEquiv which identifies X ⟶ Y⟦n⟧ and op Y ⟶ (op X)⟦n⟧ for any objects X and Y in C, and n : ℤ.
Along with the compatibilities that are obtained, this shall be the main ingredient in the construction of the (contravariant) long exact sequence of Ext in abelian categories #15092.