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The classical theorems relating integral binary quadratic forms and ideal classes of quadratic orders have been of tremendous importance in mathematics, and many authors have given extensions of these theorems to rings other than the…

Number Theory · Mathematics 2011-04-01 Melanie Matchett Wood

We investigate local rings in which a syzygy of the residue field occurs as a direct summand of another syzygy of the field. This class of local rings includes Golod rings, Burch rings and non-trivial fiber products of local rings. For such…

Commutative Algebra · Mathematics 2025-10-29 Doan Trung Cuong , Toshinori Kobayashi

This paper deals with the graded commutative rings in which every homogeneous prime ideal is contained in a unique homogeneous maximal ideal called Gelfand graded ring. The purpose is to establish some topological and algebraic…

Commutative Algebra · Mathematics 2022-10-03 Mohamed Aqalmoun

We prove a generalization of the Poincar\'e-Birkhoff theorem for the open annulus showing that if a homeomorphism satisfies a certain twist condition and the nonwandering set is connected, then there is a fixed point. Our main focus is the…

Dynamical Systems · Mathematics 2007-05-23 David Richeson , Jim Wiseman

In the present note we discuss two different ring structures on the set of holomorphic discrete series of a causal symmetric space of Cayley type $G/H$ and we suggest a new interpretation of Rankin-Cohen brackets in terms of intertwining…

Representation Theory · Mathematics 2007-05-23 Gerrit van Dijk , Michael Pevzner

In this paper we study generalized Gorenstein Arf rings; a class of one-dimensional Cohen-Macaulay local Arf rings that is strictly contained in the class of Gorenstein rings. We obtain new characterizations and examples of Arf rings, and…

Commutative Algebra · Mathematics 2020-08-11 Ela Celikbas , Olgur Celikbas , Shiro Goto , Naoki Taniguchi

In this work we attempt to generalize our result in [6] [7] for real rings (not just von Neumann regular real rings). In other words we attempt to characterize and construct real closure * of commutative unitary rings that are real. We also…

Rings and Algebras · Mathematics 2009-12-07 Jose Capco

Gel'fand-Dorfman bialgebra, which is both a Lie algebra and a Novikov algebra with some compatibility condition, appears in the study of Hamiltonian pairs in completely integrable systems and a class of special Lie conformal algebras called…

Rings and Algebras · Mathematics 2022-02-23 Jiajia Wen , Yanyong Hong

The question of when the derived category of a ring satisfies Brown--Adams representability is revisited via studying the transfer of pure homological dimension along definable functors: it is shown that, for any ring, the pure global…

Representation Theory · Mathematics 2026-01-15 Isaac Bird

Over a complete Noetherian local domain of mixed characteristic with perfect residue field, we construct a perfectoid ring which is similar to an explicit representation of a perfect closure in positive characteristic. Then we demonstrate…

Commutative Algebra · Mathematics 2025-04-25 Ryo Ishizuka , Kazuma Shimomoto

Building on his reduction to the case of an unramified complete regular local ring R of mixed characteristic, we propose a proof in the framework of P. Scholze's perfectoid theory. The main ingredients are the perfectoid "Abhyankar lemma"…

Algebraic Geometry · Mathematics 2016-09-02 Yves Andre

The aim of this article is to study basic structures and interrelations of $\delta$-rings, perfectoid towers, and lim Cohen-Macaulay sequences over Noetherian rings in positive or mixed characteristic. Then we discuss some methods for…

Commutative Algebra · Mathematics 2025-09-16 Shinnosuke Ishiro , Kazuma Shimomoto

Through the subsequent discussion we consider a certain particular sort of (topological) algebras, which may substitute the `` structure sheaf algebras'' in many--in point of fact, in all--the situations of a geometrical character that…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Anastasios Mallios

The theorem of Greenberg-Kazhdan-Drinfeld describes the formal neighborhood of a closed arc. After giving a complete proof with examples, two possible versions for the relative case of the theorem are discussed. Each one is shown to hold…

Algebraic Geometry · Mathematics 2015-12-23 Peter Petrov

The K-theory of a functor may be viewed as a relative version of the K-theory of a ring. In the case of a Galois extension of a number field F/L with rings of integers A/B respectively, this K-theory of the "norm functor" is an extension of…

K-Theory and Homology · Mathematics 2009-09-29 Max Karoubi , Thierry Lambre

We develop a general theory of extensions of flat functors along geometric morphisms of toposes, and apply it to the study of the class of theories whose classifying topos is equivalent to a presheaf topos. As a result, we obtain a…

Category Theory · Mathematics 2014-06-23 Olivia Caramello

Given a diagram of rings, one may consider the category of modules over them. We are interested in the homotopy theory of categories of this type: given a suitable diagram of model categories M(s) (as s runs through the diagram), we…

Algebraic Topology · Mathematics 2013-09-27 J. P. C. Greenlees , B. Shipley

In this paper, we establish the global analogues of some dualities and equivalences in local algebra by developing the theory of relative Cohen-Macaulay modules. Let R be a commutative Noetherian ring (not necessarily local) with identity…

Commutative Algebra · Mathematics 2023-08-22 Parisa Pourghobadian , Kamran Divaani-Aazar , Ahad Rahimi

Gelfand - Na\u{i}mark theorem supplies a one to one correspondence between commutative $C^*$-algebras and locally compact Hausdorff spaces. So any noncommutative $C^*$-algebra can be regarded as a generalization of a topological space.…

Operator Algebras · Mathematics 2014-11-11 Petr R. Ivankov

In this paper, we introduce variants of formal nearby cycles for a locally noetherian formal scheme over a complete discrete valuation ring. If the formal scheme is locally algebraizable, then our nearby cycle gives a generalization of…

Algebraic Geometry · Mathematics 2019-02-20 Yoichi Mieda