{"title":"Corrigendum and addendum to “Transitive permutation groups where nontrivial elements have at most two fixed points” [J. Pure Appl. Algebra 219(4) (2015) 729–759]","authors":"Paula Hähndel, Rebecca Waldecker","doi":"10.1016/j.jpaa.2025.108006","DOIUrl":"10.1016/j.jpaa.2025.108006","url":null,"abstract":"<div><div>This article revisits earlier work by the second author together with Kay Magaard. We correct several little results and we briefly discuss why, fortunately, the errors hardly affect our main theorems and in particular do not affect the classification of simple groups that act with fixity 2.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108006"},"PeriodicalIF":0.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167252","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":"The canonical ideal and the deformation theory of curves with automorphisms","authors":"Aristides Kontogeorgis, Alexios Terezakis","doi":"10.1016/j.jpaa.2025.108002","DOIUrl":"10.1016/j.jpaa.2025.108002","url":null,"abstract":"<div><div>The deformation theory of curves is studied by using the canonical ideal. The deformation problem of curves with automorphisms is reduced to a deformation problem of linear representations.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108002"},"PeriodicalIF":0.7,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167251","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":"Polynomial differential systems with invariant algebraic curves of arbitrary degree formed by Legendre polynomials","authors":"Jaume Llibre , Claudia Valls","doi":"10.1016/j.jpaa.2025.108001","DOIUrl":"10.1016/j.jpaa.2025.108001","url":null,"abstract":"<div><div>In 1891 Poincaré asked: <em>Given</em> <span><math><mi>m</mi><mo>≥</mo><mn>2</mn></math></span><em>, is there a positive integer</em> <span><math><mi>M</mi><mo>(</mo><mi>m</mi><mo>)</mo></math></span> <em>such that if a polynomial differential system of degree m has an invariant algebraic curve of degree</em> <span><math><mo>≥</mo><mi>M</mi><mo>(</mo><mi>m</mi><mo>)</mo></math></span><em>, then it has a rational first integral?</em> Brunella and Mendes repeated the same open question in 2000, and Lins-Neto in 2002. Between the years 2001 and 2003 three different families of quadratic polynomial differential systems provided a negative answer to this question. One of the answers used the Hermite polynomials. Recently a new negative answer was provided for polynomial differential systems of arbitrary degree using the Laguerre polynomials.</div><div>In this paper we provide another new negative answer but using for first time the Legendre polynomials. So the orthogonal polynomials play a role in the Poincaré's question. Moreover we classify the phase portraits of these polynomial differential systems having invariant algebraic curves of arbitrary degree based on the Legendre polynomials.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108001"},"PeriodicalIF":0.7,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167248","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":"Symmetric and exterior squares of hook representations","authors":"Szabolcs Mészáros , János Wolosz","doi":"10.1016/j.jpaa.2025.108003","DOIUrl":"10.1016/j.jpaa.2025.108003","url":null,"abstract":"<div><div>We determine the multiplicities of irreducible summands in the symmetric and the exterior squares of hook representations of symmetric groups over a field of characteristic zero.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108003"},"PeriodicalIF":0.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167249","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":"Quantifier-free formulas and quantifier alternation depth in doctrines","authors":"Marco Abbadini , Francesca Guffanti","doi":"10.1016/j.jpaa.2025.108004","DOIUrl":"10.1016/j.jpaa.2025.108004","url":null,"abstract":"<div><div>This paper aims to incorporate the notion of quantifier-free formulas modulo a first-order theory and the stratification of formulas by quantifier alternation depth modulo a first-order theory into the algebraic treatment of classical first-order logic.</div><div>The set of quantifier-free formulas modulo a theory is axiomatized by what we call a <em>quantifier-free fragment</em> of a Boolean doctrine with quantifiers. Rather than being an intrinsic notion, a quantifier-free fragment is an additional structure on a Boolean doctrine with quantifiers. Under a smallness assumption, the structures occurring as quantifier-free fragments of some Boolean doctrine with quantifiers are precisely the Boolean doctrines (without quantifiers). In particular, every Boolean doctrine over a small category is a quantifier-free fragment of its quantifier completion.</div><div>Furthermore, the sequences obtained by stratifying an algebra of formulas by quantifier alternation depth modulo a theory are axiomatized by what we call <em>QA-stratified Boolean doctrines</em>. While quantifier-free fragments are defined in relation to an “ambient” Boolean doctrine with quantifiers, a QA-stratified Boolean doctrine requires no such ambient doctrine, and it consists of a sequence of Boolean doctrines (without quantifiers) with connecting axioms. QA-stratified Boolean doctrines are in one-to-one correspondence with pairs consisting of a Boolean doctrine with quantifiers and a quantifier-free fragment of it.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108004"},"PeriodicalIF":0.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167253","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":"The Grothendieck group of a triangulated category","authors":"Xiao-Wu Chen , Zhi-Wei Li , Xiaojin Zhang , Zhibing Zhao","doi":"10.1016/j.jpaa.2025.108005","DOIUrl":"10.1016/j.jpaa.2025.108005","url":null,"abstract":"<div><div>We give a direct proof of the following known result: the Grothendieck group of a triangulated category with a silting subcategory is isomorphic to the split Grothendieck group of the silting subcategory. Moreover, we obtain its cluster-tilting analogue.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108005"},"PeriodicalIF":0.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144147341","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":"Random unipotent Sylow subgroups of groups of Lie type of bounded rank","authors":"Saveliy V. Skresanov","doi":"10.1016/j.jpaa.2025.108007","DOIUrl":"10.1016/j.jpaa.2025.108007","url":null,"abstract":"<div><div>In 2001 Liebeck and Pyber showed that a finite simple group of Lie type is a product of 25 carefully chosen unipotent Sylow subgroups. Later, in a series of works it was shown that 4 unipotent Sylow subgroups suffice. We prove that if the rank of a finite simple group of Lie type <em>G</em> is bounded, then <em>G</em> is a product of 11 random unipotent Sylow subgroups with probability tending to 1 as <span><math><mo>|</mo><mi>G</mi><mo>|</mo></math></span> tends to infinity. An application of the result to finite linear groups is given. The proofs do not depend on the classification of finite simple groups.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 8","pages":"Article 108007"},"PeriodicalIF":0.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167250","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 structure of finitely generated modules and the unmixed degrees","authors":"Nguyen Tu Cuong , Pham Hung Quy","doi":"10.1016/j.jpaa.2025.108000","DOIUrl":"10.1016/j.jpaa.2025.108000","url":null,"abstract":"<div><div>Let <span><math><mo>(</mo><mi>R</mi><mo>,</mo><mi>m</mi><mo>)</mo></math></span> be the homomorphic image of a Cohen-Macaulay local ring and <em>M</em> a finitely generated <em>R</em>-module. We use the splitting of local cohomology to shed a new light on the structure of non-Cohen-Macaulay modules. Namely, we show that every finitely generated <em>R</em>-module <em>M</em> is associated to a sequence of invariant modules. This module sequence expresses the deviation of <em>M</em> with the Cohen-Macaulay property. Our result generalizes the unmixed theorem of Cohen-Macaulayness for any finitely generated <em>R</em>-module. As an application we construct a new extended degree in the sense of Vasconcelos.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 7","pages":"Article 108000"},"PeriodicalIF":0.7,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084257","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":"Borel-type subalgebras of the lattice vertex operator algebra","authors":"Jianqi Liu","doi":"10.1016/j.jpaa.2025.107999","DOIUrl":"10.1016/j.jpaa.2025.107999","url":null,"abstract":"<div><div>In this paper, we introduce and study new classes of sub-vertex operator algebras of the lattice vertex operator algebras (VOAs), which we call the conic, Borel, and parabolic-type subVOAs. These CFT-type VOAs, which are not necessarily strongly finitely generated, satisfy properties similar to the usual Borel and parabolic subalgebras of a Lie algebra. For the lowest-rank nontrivial example of Borel-type subVOA <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> of <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>Z</mi><mi>α</mi></mrow></msub></math></span>, we explicitly determine its Zhu's algebra <span><math><mi>A</mi><mo>(</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>B</mi></mrow></msub><mo>)</mo></math></span> in terms of generators and relations.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 7","pages":"Article 107999"},"PeriodicalIF":0.7,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144098469","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":"Absolute algebras, contramodules, and duality squares","authors":"Victor Roca i Lucio","doi":"10.1016/j.jpaa.2025.107998","DOIUrl":"10.1016/j.jpaa.2025.107998","url":null,"abstract":"<div><div>Absolute algebras are a new type of algebraic structures, endowed with a meaningful notion of infinite sums of operations without supposing any underlying topology. Opposite to the usual definition of operadic calculus, they are defined as algebras over cooperads. The goal of this article is to develop this new theory. First, we relate the homotopy theory of absolute algebras to the homotopy theory of usual algebras via a <em>duality square</em>. It intertwines bar-cobar adjunctions with linear duality adjunctions. In particular, we show that linear duality functors between types of coalgebras and types of algebras are Quillen functors and that they induce equivalences between objects with finiteness conditions on their homology. We give general comparison results between absolute types of algebras and their classical counterparts. We work out examples of this theory such as absolute associative algebras and absolute Lie algebras, and show that it includes the theory of contramodules. Finally, in <span><span>[9]</span></span>, the authors showed that two nilpotent Lie algebras whose universal enveloping algebras are isomorphic as associative algebras must be isomorphic. As an application of our results, we generalize their theorem to the setting of absolute Lie algebras and absolute <span><math><msub><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-algebras.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 7","pages":"Article 107998"},"PeriodicalIF":0.7,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107715","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}