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We prove that for any finite-dimensional differential graded algebra with separable semisimple part the category of perfect modules is equivalent to a full subcategory of the category of perfect complexes on a smooth projective scheme with…

Algebraic Geometry · Mathematics 2020-03-18 Dmitri Orlov

It is proved that the sum of the Loewy lengths of the homology modules of a finite free complex F over a local ring R is bounded below by a number depending only on R. This result uncovers, in the structure of modules of finite projective…

Commutative Algebra · Mathematics 2010-05-20 L. L. Avramov , R. -O. Buchweitz , S. B. Iyengar , C. Miller

We prove the finiteness of leaps of modules of $m$-integrable derivations for algebras essentially of finite type and, more generally, for schemes essentially of finite type over an algebraically closed field of positive characteristic.…

Algebraic Geometry · Mathematics 2026-01-21 Takuya Miyamoto

We prove two theorems on cohomologically complete complexes. These theorems are inspired by, and yield an alternative proof of, a recent theorem of P. Schenzel on complete modules.

Commutative Algebra · Mathematics 2014-04-30 Amnon Yekutieli

Inspired by a recent work of Buchweitz and Flenner, we show that, for a semidualizing bimodule $C$, $C$--perfect complexes have the ability to detect when a ring is strongly regular. It is shown that there exists a class of modules which…

Commutative Algebra · Mathematics 2015-06-22 Ensiyeh Amanzadeh , Mohammad T. Dibaei

We prove that the depth formula holds for two finitely generated Tor-independent modules over Cohen-Macaulay local rings if one of the modules considered has finite reducing projective dimension (for example, if it has finite projective…

Commutative Algebra · Mathematics 2023-12-13 Olgur Celikbas , Toshinori Kobayashi , Brian Laverty , Hiroki Matsui

Inspired from the work of P. Scholze on the finiteness of \(\mathbf{F}_{p}\)-cohomology groups of proper rigid-analytic varieties over \(p\)-adic fields, Zavyalov recently introduced the notion of almost coherent rings, which plays a key…

Commutative Algebra · Mathematics 2026-01-21 Xiaolei Zhang

We give a new proof of the fact that any finite quadratic module can be decomposed into indecomposable ones. For any indecomposable finite quadratic module, we construct a lattice, and a positive definite lattice, both of which are of the…

Number Theory · Mathematics 2023-08-31 Xiao-Jie Zhu

In 2004 and 2005 Enochs et al. characterized the flat and projective quiver-representations of left rooted quivers. The proofs can be understood as filtering the classes $\Phi(\operatorname{Add}\mathscr X)$ and $\Phi(\varinjlim\mathscr X)$…

Category Theory · Mathematics 2018-05-14 Rune Harder Bak

As a special case of Bass' theory of perfect rings, one obtains the assertion that, over a finite-dimensional associative algebra over a field, all flat modules are projective. In this paper we prove the following relative version of this…

Rings and Algebras · Mathematics 2026-05-01 Leonid Positselski

For modules over a finite-dimensional algebra, there is a canonical one-to-one correspondence between the projective indecomposable modules and the simple modules. In this purely expository note, we take a straight-line path from the…

Rings and Algebras · Mathematics 2014-10-15 Tom Leinster

We develop in this paper a stable theory for projective complexes, by which we mean to consider a chain complex of finitely generated projective modules as an object of the factor category of the homotopy category modulo split complexes. As…

Commutative Algebra · Mathematics 2022-03-09 Yuji Yoshino

We prove smoothness in the dg sense of the bounded derived category of finitely generated modules over any finite-dimensional algebra over a perfect field, hereby answering a question of Iyama. More generally, we prove this statement for…

Algebraic Geometry · Mathematics 2019-03-25 Alexey Elagin , Valery A. Lunts , Olaf M. Schnürer

We prove a descent result for finite projective modules, motivated by a question in perfectoid geometry. Given a commutative ring $A$, we formulate a descent problem for descending a finite projective module over the Novikov ring with…

Commutative Algebra · Mathematics 2026-02-10 Dongryul Kim

We show that every finitely generated cohomologically trivial module over $RG$, where $G$ is a finite $p$-group and $R$ is a $p$-adic ring, splits as the direct sum of a finite cohomologically trivial $RG$-module and a free $RG$-module.…

Group Theory · Mathematics 2025-10-24 Yassine Guerboussa , Maria Guedri

We classify finitely generated modules over a class of algebras introduced in the authors' Ph.D thesis, called complete gentle algebras. These rings generalise the finite-dimensional gentle algebras introduced by Assem and Skowro\'{n}ski,…

Representation Theory · Mathematics 2021-07-21 Raphael Bennett-Tennenhaus

Suppose O is a complete discrete valuation ring of positive characteristic with perfect residue field. The category of finite flat strict modules was introduced recently by Faltings and appears as an equal characteristic analogue of the…

Number Theory · Mathematics 2007-05-23 Victor Abrashkin

We define a notion of total acyclicity for complexes of flat quasi-coherent sheaves over a semi-separated noetherian scheme, generalising complete flat resolutions over a ring. By studying these complexes as objects of the pure derived…

Algebraic Geometry · Mathematics 2009-02-19 Daniel Murfet , Shokrollah Salarian

We continue our study of relatively divisible and relatively flat objects in exact categories in the sense of Quillen with several applications to exact structures on finitely accessible additive categories and module categories. We derive…

Rings and Algebras · Mathematics 2018-10-30 Septimiu Crivei , Derya Keskin Tütüncü

We give a self-contained exposition of the proof of faithfully flat descent for projectivity of modules. This fills a gap in the proof given in the literature.

Commutative Algebra · Mathematics 2010-11-02 Alexander Perry