{"title":"Corrigendum to “Trace forms on the cyclotomic Hecke algebras and cocenters of the cyclotomic Schur algebras” [J. Pure Appl. Algebra 227(4) (2023) 107281]","authors":"Zhekun He , Jun Hu , Huang Lin","doi":"10.1016/j.jpaa.2025.107981","DOIUrl":"10.1016/j.jpaa.2025.107981","url":null,"abstract":"","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107981"},"PeriodicalIF":0.7,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895031","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}
{"title":"Le théorème de Lüroth pour les corps de fractions tordus par un automorphisme fini","authors":"Bruno Deschamps","doi":"10.1016/j.jpaa.2025.107982","DOIUrl":"10.1016/j.jpaa.2025.107982","url":null,"abstract":"<div><div>The main object of this article is to show the generalization of Lüroth's theorem to the case of a skew fraction field <span><math><mi>H</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>σ</mi><mo>)</mo></math></span>, where <em>H</em> denotes a field of finite dimension over its center and <span><math><mi>σ</mi><mo>∈</mo><mtext>Aut</mtext><mo>(</mo><mi>H</mi><mo>)</mo></math></span> an automorphism of finite order.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107982"},"PeriodicalIF":0.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904150","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}
{"title":"On groups with at most five irrational conjugacy classes","authors":"Gabriel A.L. Souza","doi":"10.1016/j.jpaa.2025.107980","DOIUrl":"10.1016/j.jpaa.2025.107980","url":null,"abstract":"<div><div>Much work has been done to study groups with few rational conjugacy classes or few rational irreducible characters. In this paper we look at the opposite extreme. Let <em>G</em> be a finite group. Given a conjugacy class <em>K</em> of <em>G</em>, we say it is <em>irrational</em> if there is some <span><math><mi>χ</mi><mo>∈</mo><mi>Irr</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> such that <span><math><mi>χ</mi><mo>(</mo><mi>K</mi><mo>)</mo><mo>∉</mo><mi>Q</mi></math></span>. One of our main results shows that, when <em>G</em> contains at most 5 irrational conjugacy classes, then <span><math><mo>|</mo><msub><mrow><mi>Irr</mi></mrow><mrow><mi>Q</mi></mrow></msub><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo><mo>=</mo><mo>|</mo><msub><mrow><mi>Cl</mi></mrow><mrow><mi>Q</mi></mrow></msub><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></math></span>. This suggests some duality with the known results and open questions on groups with few rational irreducible characters. Our results are independent of the Classification of Finite Simple Groups.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107980"},"PeriodicalIF":0.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904148","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}
{"title":"Biased elementary doctrines and quotient completions","authors":"Cipriano Junior Cioffo","doi":"10.1016/j.jpaa.2025.107983","DOIUrl":"10.1016/j.jpaa.2025.107983","url":null,"abstract":"<div><div>In this work, we fill the gap between the elementary quotient completion introduced by Maietti and Rosolini and the exact completion of a category with weak finite limits, as described by Carboni and Vitale. To achieve this, we generalize Lawvere's elementary doctrines to apply to categories with weak finite products, referring to these structures as biased elementary doctrines. We present two main constructions: the first, called strictification, produces an elementary doctrine from a biased one, while the second is an extension of the elementary quotient completion that generalizes the exact completion of a category with weak finite limits, even when weak finite products are involved.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107983"},"PeriodicalIF":0.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905950","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}
{"title":"On the hyperfields associated to valued fields","authors":"Alessandro Linzi , Pierre Touchard","doi":"10.1016/j.jpaa.2025.107985","DOIUrl":"10.1016/j.jpaa.2025.107985","url":null,"abstract":"<div><div>One can associate an inverse system of valued hyperfields <span><math><msub><mrow><mo>(</mo><msub><mrow><mi>H</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>I</mi></mrow></msub></math></span> to a valued field in a natural way. We investigate when, conversely, such a system arises from a valued field. First, we extend a result of Krasner by showing that the inverse limit of certain systems are stringent valued hyperfields. Secondly, we describe a Hahn-like construction which yields a henselian valued field from a stringent valued hyperfield. In addition, we provide an axiomatisation of the theory of stringent valued hyperfields in a language consisting of two binary function symbols, ⊕ and ⋅, and two constant symbols, <strong>0</strong> and <strong>1</strong>.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107985"},"PeriodicalIF":0.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906188","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}
{"title":"Silting interval reduction and 0-Auslander extriangulated categories","authors":"Jixing Pan , Bin Zhu","doi":"10.1016/j.jpaa.2025.107978","DOIUrl":"10.1016/j.jpaa.2025.107978","url":null,"abstract":"<div><div>We give a reduction technique for silting intervals in extriangulated categories, which we call silting interval reduction. It provides a reduction technique for tilting subcategories when the extriangulated categories are exact categories.</div><div>In 0-Auslander extriangulated categories (a generalization of the well-known two-term category <span><math><msup><mrow><mi>K</mi></mrow><mrow><mo>[</mo><mo>−</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo>]</mo></mrow></msup><mo>(</mo><mrow><mi>proj</mi></mrow><mi>Λ</mi><mo>)</mo></math></span> for an Artin algebra Λ), we provide a reduction theory for silting objects as an application of silting interval reduction. It unifies two-term silting reduction and Iyama-Yoshino's 2-Calabi-Yau reduction. The mutation theory developed by Gorsky, Nakaoka and Palu recently can be deduced from it. Since there are bijections between the silting objects and the support <em>τ</em>-tilting modules over certain finite dimensional algebras, we show it is compatible with <em>τ</em>-tilting reduction. This compatibility theorem also unifies the two compatibility theorems obtained by Jasso in his work on <em>τ</em>-tilting reduction.</div><div>We give a new construction for 0-Auslander extriangulated categories using silting mutation, together with silting interval reduction, we obtain some results on silting quivers. Finally, we prove that <em>d</em>-Auslander extriangulated categories are related to a certain sequence of silting mutations.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107978"},"PeriodicalIF":0.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904149","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}
{"title":"On the injective self-maps of algebraic varieties","authors":"Indranil Biswas , Nilkantha Das","doi":"10.1016/j.jpaa.2025.107988","DOIUrl":"10.1016/j.jpaa.2025.107988","url":null,"abstract":"<div><div>A conjecture of Miyanishi says that an endomorphism of an algebraic variety, defined over an algebraically closed field of characteristic zero, is an automorphism if the endomorphism is injective outside a closed subset of codimension at least 2. We prove the conjecture in the following cases:<ul><li><span>(1)</span><span><div>The variety is non-singular.</div></span></li><li><span>(2)</span><span><div>The variety is a surface.</div></span></li><li><span>(3)</span><span><div>The variety is locally a complete intersection that is regular in codimension 2.</div></span></li></ul> We also discuss a few instances where an endomorphism of a variety, satisfying the hypothesis of the conjecture of Miyanishi, induces an automorphism of the non-singular locus of the variety. Under additional hypotheses, we prove that the conjecture holds when the variety has only isolated singularities.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107988"},"PeriodicalIF":0.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883219","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}
{"title":"Symplectic period for a representation of GLn(D)","authors":"Hariom Sharma, Mahendra Kumar Verma","doi":"10.1016/j.jpaa.2025.107976","DOIUrl":"10.1016/j.jpaa.2025.107976","url":null,"abstract":"<div><div>Let <em>n</em> be a natural number, taking the value 3 or 4. Let D be a quaternion division algebra over a non-archimedean local field k of characteristic zero, and let <span><math><msub><mrow><mi>Sp</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>(</mo><mi>D</mi><mo>)</mo></math></span> be the unique non-split inner form of the symplectic group <span><math><msub><mrow><mi>Sp</mi></mrow><mrow><mn>2</mn><mi>n</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo></math></span>. This paper classifies those irreducible admissible representations of <span><math><msub><mrow><mi>GL</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>(</mo><mi>D</mi><mo>)</mo></math></span> that admit a symplectic period, that is, those irreducible admissible representations <span><math><mo>(</mo><mi>π</mi><mo>,</mo><mi>V</mi><mo>)</mo></math></span> of <span><math><msub><mrow><mi>GL</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>(</mo><mi>D</mi><mo>)</mo></math></span> which have a linear functional <em>l</em> on <em>V</em> such that <span><math><mi>l</mi><mo>(</mo><mi>π</mi><mo>(</mo><mi>h</mi><mo>)</mo><mi>v</mi><mo>)</mo><mo>=</mo><mi>l</mi><mo>(</mo><mi>v</mi><mo>)</mo></math></span> for all <span><math><mi>v</mi><mo>∈</mo><mi>V</mi></math></span> and <span><math><mi>h</mi><mo>∈</mo><msub><mrow><mi>Sp</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>(</mo><mi>D</mi><mo>)</mo></math></span>. Our results also contain all unitary representations having a symplectic period, as stated in Prasad's conjecture.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107976"},"PeriodicalIF":0.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887581","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}
{"title":"Quiver Hecke algebras for Borcherds-Cartan datum II","authors":"Bolun Tong , Wan Wu","doi":"10.1016/j.jpaa.2025.107977","DOIUrl":"10.1016/j.jpaa.2025.107977","url":null,"abstract":"<div><div>We give the crystal structure of the Grothendieck group <span><math><msub><mrow><mi>G</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mi>R</mi><mo>)</mo></math></span> of irreducible modules over the quiver Hecke algebra <em>R</em> constructed in <span><span>[15]</span></span>. This leads to the categorification of the crystal <span><math><mi>B</mi><mo>(</mo><mo>∞</mo><mo>)</mo></math></span> of the quantum Borcherds algebra <span><math><msub><mrow><mi>U</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>(</mo><mi>g</mi><mo>)</mo></math></span> and its irreducible highest weight crystal <span><math><mi>B</mi><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> for arbitrary Borcherds-Cartan data. Additionally, we study the cyclotomic categorification of irreducible highest weight <span><math><msub><mrow><mi>U</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>(</mo><mi>g</mi><mo>)</mo></math></span>-modules.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 6","pages":"Article 107977"},"PeriodicalIF":0.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905949","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}
{"title":"Tensor product of A∞-categories","authors":"Mattia Ornaghi","doi":"10.1016/j.jpaa.2025.107987","DOIUrl":"10.1016/j.jpaa.2025.107987","url":null,"abstract":"<div><div>In this paper we define the tensor product of two <span><math><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-categories and two <span><math><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-functors. This tensor product makes the category of <span><math><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-categories symmetric monoidal (up to homotopy), and the category <span><math><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub><msup><mrow><mi>Cat</mi></mrow><mrow><mi>u</mi></mrow></msup><mo>/</mo><mo>≈</mo></math></span> a closed symmetric monoidal category. Moreover, we define the derived tensor product making <span><math><mtext>Ho</mtext><mo>(</mo><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub><mrow><mi>Cat</mi></mrow><mo>)</mo></math></span>, the homotopy category of the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-categories, a closed symmetric monoidal category. We also provide an explicit description of the internal homs in terms of <span><math><msub><mrow><mi>A</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-functors.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 7","pages":"Article 107987"},"PeriodicalIF":0.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887019","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}