English

Co-t-structures, cotilting and cotorsion pairs

Category Theory 2020-09-30 v2 Algebraic Geometry Representation Theory

Abstract

Let T\mathsf{T} be a triangulated category with shift functor Σ ⁣:TT\Sigma \colon \mathsf{T} \to \mathsf{T}. Suppose (A,B)(\mathsf{A},\mathsf{B}) is a co-t-structure with coheart S=ΣAB\mathsf{S} = \Sigma \mathsf{A} \cap \mathsf{B} and extended coheart C=Σ2AB=SΣS\mathsf{C} = \Sigma^2 \mathsf{A} \cap \mathsf{B} = \mathsf{S} * \Sigma \mathsf{S}, which is an extriangulated category. We show that there is a bijection between co-t-structures (A,B)(\mathsf{A}',\mathsf{B}') in T\mathsf{T} such that AAΣA\mathsf{A} \subseteq \mathsf{A}' \subseteq \Sigma \mathsf{A} and complete cotorsion pairs in the extended coheart C\mathsf{C}. In the case that T\mathsf{T} is Hom-finite, k\mathbf{k}-linear and Krull-Schmidt, we show further that there is a bijection between complete cotorsion pairs in C\mathsf{C} and functorially finite torsion pairs in modS\mathsf{mod}\, \mathsf{S}.

Keywords

Cite

@article{arxiv.2007.06536,
  title  = {Co-t-structures, cotilting and cotorsion pairs},
  author = {David Pauksztello and Alexandra Zvonareva},
  journal= {arXiv preprint arXiv:2007.06536},
  year   = {2020}
}

Comments

15 pages, 2 figures

R2 v1 2026-06-23T17:05:04.548Z