Pub Date : 2025-09-02DOI: 10.1016/j.jpaa.2025.108077
Piotr Grzeszczuk
This paper examines the Jacobson radical of tensor products of associative algebras over a field k focusing on algebras with a special type of ordering. The notion of almost ordered algebras is introduced. It is proved that for any k-algebra A and an almost ordered algebra B the Jacobson radical , where N is the nil radical of A. We apply this result to cases where the algebra A either satisfies a polynomial identity or is a Goldie algebra.
{"title":"Almost ordered algebras and the Jacobson radical of tensor products","authors":"Piotr Grzeszczuk","doi":"10.1016/j.jpaa.2025.108077","DOIUrl":"10.1016/j.jpaa.2025.108077","url":null,"abstract":"<div><div>This paper examines the Jacobson radical of tensor products of associative algebras over a field <strong>k</strong> focusing on algebras with a special type of ordering. The notion of almost ordered algebras is introduced. It is proved that for any <strong>k</strong>-algebra <em>A</em> and an almost ordered algebra <em>B</em> the Jacobson radical <span><math><mi>J</mi><mo>(</mo><mi>A</mi><msub><mrow><mo>⊗</mo></mrow><mrow><mi>k</mi></mrow></msub><mi>B</mi><mo>)</mo><mo>⊆</mo><mi>N</mi><msub><mrow><mo>⊗</mo></mrow><mrow><mi>k</mi></mrow></msub><mi>B</mi></math></span>, where <em>N</em> is the nil radical of <em>A</em>. We apply this result to cases where the algebra <em>A</em> either satisfies a polynomial identity or is a Goldie algebra.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108077"},"PeriodicalIF":0.8,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-02DOI: 10.1016/j.jpaa.2025.108079
Antonino Ficarra , Ayesha Asloob Qureshi
Let G be a finite simple graph, and let denote its edge ideal. In this paper, we investigate the asymptotic behavior of the syzygies of powers of edge ideals through the lens of homological shift ideals . We introduce the notion of the ith homological strong persistence property for monomial ideals I, providing an algebraic characterization that ensures the chain of inclusions . We prove that edge ideals possess both the 0th and 1st homological strong persistence properties. To this end, we explicitly describe the first homological shift algebra of and show that for all . Finally, we conjecture that if has a linear resolution, then also has a linear resolution for all , and we present partial results supporting this conjecture.
{"title":"Edge ideals and their asymptotic syzygies","authors":"Antonino Ficarra , Ayesha Asloob Qureshi","doi":"10.1016/j.jpaa.2025.108079","DOIUrl":"10.1016/j.jpaa.2025.108079","url":null,"abstract":"<div><div>Let <em>G</em> be a finite simple graph, and let <span><math><mi>I</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> denote its edge ideal. In this paper, we investigate the asymptotic behavior of the syzygies of powers of edge ideals through the lens of homological shift ideals <span><math><msub><mrow><mtext>HS</mtext></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><mi>I</mi><msup><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mrow><mi>k</mi></mrow></msup><mo>)</mo></math></span>. We introduce the notion of the <em>i</em>th homological strong persistence property for monomial ideals <em>I</em>, providing an algebraic characterization that ensures the chain of inclusions <span><math><mtext>Ass</mtext><mspace></mspace><msub><mrow><mtext>HS</mtext></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><mi>I</mi><mo>)</mo><mo>⊆</mo><mtext>Ass</mtext><mspace></mspace><msub><mrow><mtext>HS</mtext></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><msup><mrow><mi>I</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo><mo>⊆</mo><mtext>Ass</mtext><mspace></mspace><msub><mrow><mtext>HS</mtext></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><msup><mrow><mi>I</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>)</mo><mo>⊆</mo><mo>⋯</mo></math></span>. We prove that edge ideals possess both the 0th and 1st homological strong persistence properties. To this end, we explicitly describe the first homological shift algebra of <span><math><mi>I</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> and show that <span><math><msub><mrow><mtext>HS</mtext></mrow><mrow><mn>1</mn></mrow></msub><mo>(</mo><mi>I</mi><msup><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mrow><mi>k</mi><mo>+</mo><mn>1</mn></mrow></msup><mo>)</mo><mo>=</mo><mi>I</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>⋅</mo><msub><mrow><mtext>HS</mtext></mrow><mrow><mn>1</mn></mrow></msub><mo>(</mo><mi>I</mi><msup><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mrow><mi>k</mi></mrow></msup><mo>)</mo></math></span> for all <span><math><mi>k</mi><mo>≥</mo><mn>1</mn></math></span>. Finally, we conjecture that if <span><math><mi>I</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> has a linear resolution, then <span><math><msub><mrow><mtext>HS</mtext></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><mi>I</mi><msup><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mrow><mi>k</mi></mrow></msup><mo>)</mo></math></span> also has a linear resolution for all <span><math><mi>k</mi><mo>≫</mo><mn>0</mn></math></span>, and we present partial results supporting this conjecture.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108079"},"PeriodicalIF":0.8,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-29DOI: 10.1016/j.jpaa.2025.108075
Kateřina Fuková, Jan Trlifaj
Let R be a semiartinian (von Neumann) regular ring with primitive factors artinian. The dimension sequence is an invariant that captures the various skew-fields and dimensions occurring in the layers of the socle sequence of R. Though does not determine R up to an isomorphism even for rings of Loewy length 2, we prove that it does so when R is a commutative semiartinian regular K-algebra of countable type over a field K. The proof is constructive: given the sequence , we construct the unique K-algebra of countable type such that by a transfinite iterative construction from the base case of the K-algebra consisting of all eventually constant sequences in . Moreover, we prove that the K-algebras possess conormed strong multiplicative bases despite the fact that the ambient K-algebras do not even have any bounded bases for any infinite cardinal κ.
Recently, a study of the number of limit models in AECs of modules [9] has raised interest in the question of existence of strictly λ-injective modules for arbitrary infinite cardinals λ. In the final section, we construct examples of such modules over the K-algebra for each cardinal .
{"title":"Multiplicative bases and commutative semiartinian von Neumann regular algebras","authors":"Kateřina Fuková, Jan Trlifaj","doi":"10.1016/j.jpaa.2025.108075","DOIUrl":"10.1016/j.jpaa.2025.108075","url":null,"abstract":"<div><div>Let <em>R</em> be a semiartinian (von Neumann) regular ring with primitive factors artinian. The dimension sequence <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>R</mi></mrow></msub></math></span> is an invariant that captures the various skew-fields and dimensions occurring in the layers of the socle sequence of <em>R</em>. Though <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>R</mi></mrow></msub></math></span> does not determine <em>R</em> up to an isomorphism even for rings of Loewy length 2, we prove that it does so when <em>R</em> is a commutative semiartinian regular <em>K</em>-algebra of countable type over a field <em>K</em>. The proof is constructive: given the sequence <span><math><mi>D</mi></math></span>, we construct the unique <em>K</em>-algebra of countable type <span><math><mi>R</mi><mo>=</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>α</mi><mo>,</mo><mi>n</mi></mrow></msub></math></span> such that <span><math><mi>D</mi><mo>=</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>R</mi></mrow></msub></math></span> by a transfinite iterative construction from the base case of the <em>K</em>-algebra <span><math><mi>R</mi><mo>(</mo><msub><mrow><mi>ℵ</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>,</mo><mi>K</mi><mo>)</mo></math></span> consisting of all eventually constant sequences in <span><math><msup><mrow><mi>K</mi></mrow><mrow><msub><mrow><mi>ℵ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></msup></math></span>. Moreover, we prove that the <em>K</em>-algebras <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>α</mi><mo>,</mo><mi>n</mi></mrow></msub></math></span> possess conormed strong multiplicative bases despite the fact that the ambient <em>K</em>-algebras <span><math><msup><mrow><mi>K</mi></mrow><mrow><mi>κ</mi></mrow></msup></math></span> do not even have any bounded bases for any infinite cardinal <em>κ</em>.</div><div>Recently, a study of the number of limit models in AECs of modules <span><span>[9]</span></span> has raised interest in the question of existence of strictly <em>λ</em>-injective modules for arbitrary infinite cardinals <em>λ</em>. In the final section, we construct examples of such modules over the <em>K</em>-algebra <span><math><mi>R</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>K</mi><mo>)</mo></math></span> for each cardinal <span><math><mi>κ</mi><mo>≥</mo><mi>λ</mi></math></span>.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108075"},"PeriodicalIF":0.8,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-29DOI: 10.1016/j.jpaa.2025.108074
Giulia dal Verme , Thomas Weigel
In this paper, Bass-Serre theory is developed in the groupoid framework, and a structure theorem is established. We show that, when a groupoid action on a forest is without inversion of edges, it induces a graph of groupoids. Conversely, a graph of groupoids that satisfies certain conditions admits a canonical associated groupoid, which we call the fundamental groupoid, and a forest, which we call the Bass-Serre forest. The fundamental groupoid acts on the Bass-Serre forest. The structure theorem asserts that these processes are mutually inverse.
{"title":"Bass-Serre theory for groupoids","authors":"Giulia dal Verme , Thomas Weigel","doi":"10.1016/j.jpaa.2025.108074","DOIUrl":"10.1016/j.jpaa.2025.108074","url":null,"abstract":"<div><div>In this paper, Bass-Serre theory is developed in the groupoid framework, and a structure theorem is established. We show that, when a groupoid action on a forest is without inversion of edges, it induces a graph of groupoids. Conversely, a graph of groupoids that satisfies certain conditions admits a canonical associated groupoid, which we call the fundamental groupoid, and a forest, which we call the Bass-Serre forest. The fundamental groupoid acts on the Bass-Serre forest. The structure theorem asserts that these processes are mutually inverse.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108074"},"PeriodicalIF":0.8,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144925842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-26DOI: 10.1016/j.jpaa.2025.108073
J.L. Wrigley
We establish a bi-equivalence between the bi-category of topoi with enough points and a localisation of a bi-subcategory of topological groupoids.
建立了具有足够点的拓扑双范畴与拓扑群类双子范畴的局部化之间的双等价性。
{"title":"Topoi with enough points and topological groupoids","authors":"J.L. Wrigley","doi":"10.1016/j.jpaa.2025.108073","DOIUrl":"10.1016/j.jpaa.2025.108073","url":null,"abstract":"<div><div>We establish a bi-equivalence between the bi-category of topoi with enough points and a localisation of a bi-subcategory of topological groupoids.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108073"},"PeriodicalIF":0.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-26DOI: 10.1016/j.jpaa.2025.108072
Tom de Jong , Martín Hötzel Escardó
We develop the theory of continuous and algebraic domains in constructive and predicative univalent foundations, building upon our earlier work on basic domain theory in this setting. That we work predicatively means that we do not assume Voevodsky's propositional resizing axioms. Our work is constructive in the sense that we do not rely on excluded middle or the axiom of (countable) choice. To deal with size issues and give a predicatively suitable definition of continuity of a dcpo, we follow Johnstone and Joyal's work on continuous categories. Adhering to the univalent perspective, we explicitly distinguish between data and property. To ensure that being continuous is a property of a dcpo, we turn to the propositional truncation, although we explain that some care is needed to avoid needing the axiom of choice. We also adapt the notion of a domain-theoretic basis to the predicative setting by imposing suitable smallness conditions, analogous to the categorical concept of an accessible category. All our running examples of continuous dcpos are then actually examples of dcpos with small bases which we show to be well behaved predicatively. In particular, such dcpos are exactly those presented by small ideals. As an application of the theory, we show that Scott's model of the untyped λ-calculus is an example of an algebraic dcpo with a small basis. Our work is formalised in the Agda proof assistant and its ability to infer universe levels has been invaluable for our purposes.
{"title":"Continuous and algebraic domains in univalent foundations","authors":"Tom de Jong , Martín Hötzel Escardó","doi":"10.1016/j.jpaa.2025.108072","DOIUrl":"10.1016/j.jpaa.2025.108072","url":null,"abstract":"<div><div>We develop the theory of continuous and algebraic domains in constructive and predicative univalent foundations, building upon our earlier work on basic domain theory in this setting. That we work predicatively means that we do not assume Voevodsky's propositional resizing axioms. Our work is constructive in the sense that we do not rely on excluded middle or the axiom of (countable) choice. To deal with size issues and give a predicatively suitable definition of continuity of a dcpo, we follow Johnstone and Joyal's work on continuous categories. Adhering to the univalent perspective, we explicitly distinguish between data and property. To ensure that being continuous is a property of a dcpo, we turn to the propositional truncation, although we explain that some care is needed to avoid needing the axiom of choice. We also adapt the notion of a domain-theoretic basis to the predicative setting by imposing suitable smallness conditions, analogous to the categorical concept of an accessible category. All our running examples of continuous dcpos are then actually examples of dcpos with small bases which we show to be well behaved predicatively. In particular, such dcpos are exactly those presented by small ideals. As an application of the theory, we show that Scott's <span><math><msub><mrow><mi>D</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span> model of the untyped <em>λ</em>-calculus is an example of an algebraic dcpo with a small basis. Our work is formalised in the <span>Agda</span> proof assistant and its ability to infer universe levels has been invaluable for our purposes.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108072"},"PeriodicalIF":0.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144925841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-19DOI: 10.1016/j.jpaa.2025.108071
Tony J. Puthenpurakal
Let A be a Noetherian ring and let be standard graded A-algebras with and assume we have a homogeneous inclusion of graded rings. Assume M is a finitely generated graded -module and N is a finitely generated module. Also assume as graded -modules. Let F be a covariant, coherent functor on the category of finitely generated A-modules. Then we show
(1)
is stable for .
(2)
if J is an ideal in A then is constant for .
(3)
if A is local and has finite length for all n then the function is of polynomial type.
Our technique to prove the above assertions is categorical. We define a category where we show all the above properties hold for . Finally we show
{"title":"A convenient category to study asymptotic primes and related questions","authors":"Tony J. Puthenpurakal","doi":"10.1016/j.jpaa.2025.108071","DOIUrl":"10.1016/j.jpaa.2025.108071","url":null,"abstract":"<div><div>Let <em>A</em> be a Noetherian ring and let <span><math><mi>R</mi><mo>,</mo><mi>S</mi></math></span> be standard graded <em>A</em>-algebras with <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><msub><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mi>A</mi></math></span> and assume we have a homogeneous inclusion <span><math><mi>R</mi><mo>⊆</mo><mi>S</mi></math></span> of graded rings. Assume <em>M</em> is a finitely generated graded <span><math><mi>R</mi></math></span>-module and <em>N</em> is a finitely generated <span><math><mi>S</mi></math></span> module. Also assume <span><math><mi>M</mi><mo>⊆</mo><mi>N</mi></math></span> as graded <span><math><mi>R</mi></math></span>-modules. Let <em>F</em> be a covariant, coherent functor on the category of finitely generated <em>A</em>-modules. Then we show<ul><li><span>(1)</span><span><div><span><math><msub><mrow><mi>Ass</mi></mrow><mrow><mi>A</mi></mrow></msub><mspace></mspace><mi>F</mi><mo>(</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>/</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo></math></span> is stable for <span><math><mi>n</mi><mo>≫</mo><mn>0</mn></math></span>.</div></span></li><li><span>(2)</span><span><div>if <em>J</em> is an ideal in <em>A</em> then <span><math><mi>grade</mi><mo>(</mo><mi>J</mi><mo>,</mo><mi>F</mi><mo>(</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>/</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo><mo>)</mo></math></span> is constant for <span><math><mi>n</mi><mo>≫</mo><mn>0</mn></math></span>.</div></span></li><li><span>(3)</span><span><div>if <em>A</em> is local and <span><math><mi>F</mi><mo>(</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>/</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo></math></span> has finite length for all <em>n</em> then the function <span><math><mi>n</mi><mo>↦</mo><mi>ℓ</mi><mo>(</mo><mi>F</mi><mo>(</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>/</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo><mo>)</mo></math></span> is of polynomial type.</div></span></li></ul> Our technique to prove the above assertions is categorical. We define a category <span><math><mi>A</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span> where we show all the above properties hold for <span><math><mi>X</mi><mo>∈</mo><mi>A</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span>. Finally we show <span><math><mi>M</mi><mo>/</mo><mi>N</mi><mo>∈</mo><mi>A</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span></div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108071"},"PeriodicalIF":0.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-14DOI: 10.1016/j.jpaa.2025.108067
Sakshi Gupta
{"title":"Corrigendum to “Image of ideals under linear K-derivations and the LNED conjecture” [Journal of Pure and Applied Algebra 229 (2025) 108041]","authors":"Sakshi Gupta","doi":"10.1016/j.jpaa.2025.108067","DOIUrl":"10.1016/j.jpaa.2025.108067","url":null,"abstract":"","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108067"},"PeriodicalIF":0.8,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144826480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-13DOI: 10.1016/j.jpaa.2025.108070
Souvik Dey , Pat Lank , Ryo Takahashi
This article investigates strong generation within the module category of a commutative Noetherian ring. We establish a criterion for such rings to possess strong generators within their module category, addressing a question raised by Iyengar and Takahashi. As a consequence, this not only demonstrates that any Noetherian quasi-excellent ring of finite Krull dimension satisfies this criterion, but applies to rings outside this class. Additionally, we identify explicit strong generators within the module category for rings of prime characteristic, and establish upper bounds on Rouquier dimension in terms of classical numerical invariants for modules.
{"title":"Strong generation for module categories","authors":"Souvik Dey , Pat Lank , Ryo Takahashi","doi":"10.1016/j.jpaa.2025.108070","DOIUrl":"10.1016/j.jpaa.2025.108070","url":null,"abstract":"<div><div>This article investigates strong generation within the module category of a commutative Noetherian ring. We establish a criterion for such rings to possess strong generators within their module category, addressing a question raised by Iyengar and Takahashi. As a consequence, this not only demonstrates that any Noetherian quasi-excellent ring of finite Krull dimension satisfies this criterion, but applies to rings outside this class. Additionally, we identify explicit strong generators within the module category for rings of prime characteristic, and establish upper bounds on Rouquier dimension in terms of classical numerical invariants for modules.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108070"},"PeriodicalIF":0.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-12DOI: 10.1016/j.jpaa.2025.108069
Alberto Castillo-Gómez, Christof Geiss
Inspired by the work of Geiss, Leclerc and Schröer [6] we realize the enveloping algebra of the positive part of an affine Kac-Moody Lie algebra of Dynkin type as a generalized composition algebra of constructible functions on the varieties of locally free representations of the corresponding 1-Iwanaga-Gorenstein algebra with minimal symmetrizer D. To this end, we exploit in several ways the fact that in this situation H is a string algebra.
{"title":"A geometric construction of U(n) for affine Kac-Moody algebras of type C˜n","authors":"Alberto Castillo-Gómez, Christof Geiss","doi":"10.1016/j.jpaa.2025.108069","DOIUrl":"10.1016/j.jpaa.2025.108069","url":null,"abstract":"<div><div>Inspired by the work of Geiss, Leclerc and Schröer <span><span>[6]</span></span> we realize the enveloping algebra of the positive part of an affine Kac-Moody Lie algebra of Dynkin type <span><math><msub><mrow><mover><mrow><mi>C</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mi>n</mi></mrow></msub></math></span> as a generalized composition algebra of constructible functions on the varieties of locally free representations of the corresponding 1-Iwanaga-Gorenstein algebra <span><math><mi>H</mi><mo>=</mo><msub><mrow><mi>H</mi></mrow><mrow><mi>C</mi></mrow></msub><mo>(</mo><mi>C</mi><mo>,</mo><mi>D</mi><mo>,</mo><mi>Ω</mi><mo>)</mo></math></span> with minimal symmetrizer <em>D</em>. To this end, we exploit in several ways the fact that in this situation <em>H</em> is a string algebra.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 10","pages":"Article 108069"},"PeriodicalIF":0.8,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}