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 …

Contraherent cosheaves

L Positselski - arXiv preprint arXiv:1209.2995, 2012 - arxiv.org
Contraherent cosheaves are globalizations of cotorsion (or similar) modules over
commutative rings obtained by gluing together over a scheme. The category of contraherent …

[HTML][HTML] New enhancements of derived categories of coherent sheaves and applications

VA Lunts, OM Schnürer - Journal of Algebra, 2016 - Elsevier
We introduce new enhancements for the bounded derived category D b (Coh (X)) of
coherent sheaves on a suitable scheme X and for its subcategory P erf (X) of perfect …

Flat comodules and contramodules as directed colimits, and cotorsion periodicity

L Positselski - arXiv preprint arXiv:2306.02734, 2023 - arxiv.org
This paper is a follow-up to arXiv: 2212.09639. We consider two algebraic settings of
comodules over a coring and contramodules over a topological ring with a countable base …

[图书][B] Semi-infinite algebraic geometry of quasi-coherent sheaves on ind-schemes: Quasi-coherent torsion sheaves, the semiderived category, and the semitensor …

L Positselski - 2023 - books.google.com
Semi-Infinite Geometry is a theory of" doubly infinite-dimensional" geometric or topological
objects. In this book the author explains what should be meant by an algebraic variety of …

[图书][B] A gentle introduction to homological mirror symmetry

R Bocklandt - 2021 - books.google.com
Homological mirror symmetry has its origins in theoretical physics but is now of great interest
in mathematics due to the deep connections it reveals between different areas of geometry …

[HTML][HTML] Model category structures arising from Drinfeld vector bundles

S Estrada, PAG Asensio, M Prest, J Trlifaj - Advances in Mathematics, 2012 - Elsevier
We present a general construction of model category structures on the category C (Qco (X))
of unbounded chain complexes of quasi-coherent sheaves on a semi-separated scheme X …

Philosophy of contraherent cosheaves

L Positselski - arXiv preprint arXiv:2311.14179, 2023 - arxiv.org
Contraherent cosheaves are module objects over algebraic varieties defined by gluing
using the colocalization functors. Contraherent cosheaves are designed to be used for …

Flat morphisms of finite presentation are very flat

L Positselski, A Slávik - Annali di Matematica Pura ed Applicata (1923-), 2020 - Springer
Principal affine open subsets in affine schemes are an important tool in the foundations of
algebraic geometry. Given a commutative ring R, R-modules built from the rings of functions …

∞-tilting theory

L Positselski, J Šťovíček - Pacific Journal of Mathematics, 2019 - msp.org
We define the notion of an infinitely generated tilting object of infinite homological dimension
in an abelian category. A one-to-one correspondence between∞-tilting objects in complete …