The tilting–cotilting correspondence

L Positselski, J Šťovíček - International Mathematics Research …, 2021 - academic.oup.com
To a big-tilting object in a complete, cocomplete abelian category with an injective
cogenerator we assign a big-cotilting object in a complete, cocomplete abelian category with …

Flat quasi-coherent sheaves as direct limits, and quasi-coherent cotorsion periodicity

L Positselski, J Stovicek - arXiv preprint arXiv:2212.09639, 2022 - arxiv.org
We show that every flat quasi-coherent sheaf on a quasi-compact quasi-separated scheme
is a directed colimit of locally countably presentable flat quasi-coherent sheaves. More …

Coderived and contraderived categories of locally presentable abelian DG-categories

L Positselski, J Stovicek - arXiv preprint arXiv:2210.08237, 2022 - arxiv.org
The concept of an abelian DG-category, introduced by the first-named author in arXiv:
2110.08237, unites the notions of abelian categories and (curved) DG-modules in a …

Locally coherent exact categories

L Positselski - arXiv preprint arXiv:2311.02418, 2023 - arxiv.org
A locally coherent exact category is a finitely accessible additive category endowed with an
exact structure in which the admissible short exact sequences are the directed colimits of the …

Fp-projective periodicity

S Bazzoni, M Hrbek, L Positselski - Journal of Pure and Applied Algebra, 2024 - Elsevier
The phenomenon of periodicity, discovered by Benson and Goodearl, is linked to the
behavior of the objects of cocycles in acyclic complexes. It is known that any flat Proj …

Weakly curved A-infinity algebras over a topological local ring

L Positselski - arXiv preprint arXiv:1202.2697, 2012 - arxiv.org
We define and study the derived categories of the first kind for curved DG and A-infinity
algebras complete over a pro-Artinian local ring with the curvature elements divisible by the …

Contramodules

L Positselski - Confluentes Mathematici, 2021 - numdam.org
Contramodules are module-like algebraic structures endowed with infinite summation (or,
occasionally, integration) operations satisfying natural axioms. Introduced originally by …

Derived, coderived, and contraderived categories of locally presentable abelian categories

L Positselski, J Šťovíček - Journal of Pure and Applied Algebra, 2022 - Elsevier
For a locally presentable abelian category B with a projective generator, we construct the
projective derived and contraderived model structures on the category of complexes …

Flatness and completion revisited

A Yekutieli - Algebras and Representation Theory, 2018 - Springer
We continue investigating the interaction between flatness and a a-adic completion for
infinitely generated A-modules. Here A is a commutative ring and aa is a finitely generated …

Contramodules over pro-perfect topological rings

L Positselski - Forum Mathematicum, 2022 - degruyter.com
For four wide classes of topological rings R, we show that all flat left R-contramodules have
projective covers if and only if all flat left R-contramodules are projective if and only if all left …