Pub Date : 2026-01-29DOI: 10.1016/j.jalgebra.2025.12.032
Chao Song , Kai Wang , Yuanyuan Zhang , Guodong Zhou
This paper is the first in a series of works devoted to an operadic study of Nijenhuis structures, focusing on Nijenhuis associative algebras. We introduce the concept of homotopy Nijenhuis associative algebras and demonstrate that the differential graded (=dg) operad governing these structures serves as the minimal model of the operad for Nijenhuis associative algebras. Additionally, we determine the Koszul dual homotopy cooperad of . We construct an -algebra that controls the simultaneous deformations of associative products and Nijenhuis operators. The Maurer-Cartan elements of this -algebra correspond bijectively to Nijenhuis associative algebra structures. From this, we derive a cochain complex (deformation complex) and an associated cohomology theory of Nijenhuis associative algebras. Finally, we explore the connection between homotopy relative Rota-Baxter associative algebras of weight 0 and homotopy Nijenhuis associative algebras. A sequel to this work will extend the study to Nijenhuis Lie algebras, with applications to Nijenhuis geometry.
{"title":"Deformations and homotopy theory of Nijenhuis associative algebras","authors":"Chao Song , Kai Wang , Yuanyuan Zhang , Guodong Zhou","doi":"10.1016/j.jalgebra.2025.12.032","DOIUrl":"10.1016/j.jalgebra.2025.12.032","url":null,"abstract":"<div><div>This paper is the first in a series of works devoted to an operadic study of Nijenhuis structures, focusing on Nijenhuis associative algebras. We introduce the concept of homotopy Nijenhuis associative algebras and demonstrate that the differential graded (=dg) operad <span><math><msub><mrow><mi>NjA</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span> governing these structures serves as the minimal model of the operad <span><math><mi>NjA</mi></math></span> for Nijenhuis associative algebras. Additionally, we determine the Koszul dual homotopy cooperad of <span><math><mi>NjA</mi></math></span>. We construct an <span><math><msub><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-algebra that controls the simultaneous deformations of associative products and Nijenhuis operators. The Maurer-Cartan elements of this <span><math><msub><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-algebra correspond bijectively to Nijenhuis associative algebra structures. From this, we derive a cochain complex (deformation complex) and an associated cohomology theory of Nijenhuis associative algebras. Finally, we explore the connection between homotopy relative Rota-Baxter associative algebras of weight 0 and homotopy Nijenhuis associative algebras. A sequel to this work will extend the study to Nijenhuis Lie algebras, with applications to Nijenhuis geometry.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"694 ","pages":"Pages 148-184"},"PeriodicalIF":0.8,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172046","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 : 2026-01-29DOI: 10.1016/j.jalgebra.2025.12.030
Naoki Endo
As part of stratification of Cohen-Macaulay rings, we introduce and develop the theory of Goto rings, generalizing the notion of almost Gorenstein rings originally defined by V. Barucci and R. Fröberg in 1997. What has dominated the series of researches on almost Gorenstein rings is the fact that the reduction numbers of extended canonical ideals are at most 2; we define Goto rings as Cohen-Macaulay rings admitting such extended canonical ideals. We provide a characterization of Goto rings in terms of the structure of Sally modules and determine the Hilbert functions of them. Various examples of Goto rings that come from numerical semigroups, idealizations, fiber products, and equimultiple Ulrich ideals are explored as well.
{"title":"Goto rings","authors":"Naoki Endo","doi":"10.1016/j.jalgebra.2025.12.030","DOIUrl":"10.1016/j.jalgebra.2025.12.030","url":null,"abstract":"<div><div>As part of stratification of Cohen-Macaulay rings, we introduce and develop the theory of Goto rings, generalizing the notion of almost Gorenstein rings originally defined by V. Barucci and R. Fröberg in 1997. What has dominated the series of researches on almost Gorenstein rings is the fact that the reduction numbers of extended canonical ideals are at most 2; we define Goto rings as Cohen-Macaulay rings admitting such extended canonical ideals. We provide a characterization of Goto rings in terms of the structure of Sally modules and determine the Hilbert functions of them. Various examples of Goto rings that come from numerical semigroups, idealizations, fiber products, and equimultiple Ulrich ideals are explored as well.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"694 ","pages":"Pages 44-108"},"PeriodicalIF":0.8,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098461","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 : 2026-01-29DOI: 10.1016/j.jalgebra.2025.12.029
Akihiro Higashitani, Koji Matsushita , Koichiro Tani
The notion of Khovanskii bases was introduced by Kaveh and Manon [6]. It is a generalization of the notion of SAGBI bases for a subalgebra of polynomials. The notion of SAGBI bases was introduced by Robbiano and Sweedler [10] as an analogue of Gröbner bases in the context of subalgebras. A Hibi ideal is an ideal of a polynomial ring that arises from a distributive lattice. For the development of an analogy of the theory of Hibi ideals and Gröbner bases within the framework of subalgebras, in this paper, we investigate when the set of the polynomials associated with a distributive lattice forms a Khovanskii basis of the subalgebras it generates. We characterize such distributive lattices and their underlying posets. In particular, generalized snake posets and -free posets appear as the characterization.
{"title":"Khovanskii bases of subalgebras arising from finite distributive lattices","authors":"Akihiro Higashitani, Koji Matsushita , Koichiro Tani","doi":"10.1016/j.jalgebra.2025.12.029","DOIUrl":"10.1016/j.jalgebra.2025.12.029","url":null,"abstract":"<div><div>The notion of Khovanskii bases was introduced by Kaveh and Manon <span><span>[6]</span></span>. It is a generalization of the notion of SAGBI bases for a subalgebra of polynomials. The notion of SAGBI bases was introduced by Robbiano and Sweedler <span><span>[10]</span></span> as an analogue of Gröbner bases in the context of subalgebras. A Hibi ideal is an ideal of a polynomial ring that arises from a distributive lattice. For the development of an analogy of the theory of Hibi ideals and Gröbner bases within the framework of subalgebras, in this paper, we investigate when the set of the polynomials associated with a distributive lattice forms a Khovanskii basis of the subalgebras it generates. We characterize such distributive lattices and their underlying posets. In particular, generalized snake posets and <span><math><mo>{</mo><mo>(</mo><mn>2</mn><mo>+</mo><mn>2</mn><mo>)</mo><mo>,</mo><mo>(</mo><mn>1</mn><mo>+</mo><mn>1</mn><mo>+</mo><mn>1</mn><mo>)</mo><mo>}</mo></math></span>-free posets appear as the characterization.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 805-823"},"PeriodicalIF":0.8,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170685","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 : 2026-01-28DOI: 10.1016/j.jalgebra.2025.12.028
Francesca Lisi, Luca Sabatini
Let G be a finite group and let be Sylow subgroups for distinct primes . We conjecture that there exists such that is inclusion-minimal in for all i. As a first step in this direction, we show that a finite group cannot be covered by (proper) Sylow normalizers for distinct primes. Then we settle the conjecture in two opposite situations: symmetric and alternating groups of large degree and metanilpotent groups of odd order. Applications concerning the intersections of nilpotent subgroups are discussed.
{"title":"Sylow subgroups for distinct primes and intersection of nilpotent subgroups","authors":"Francesca Lisi, Luca Sabatini","doi":"10.1016/j.jalgebra.2025.12.028","DOIUrl":"10.1016/j.jalgebra.2025.12.028","url":null,"abstract":"<div><div>Let <em>G</em> be a finite group and let <span><math><msubsup><mrow><mo>(</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>n</mi></mrow></msubsup></math></span> be Sylow subgroups for distinct primes <span><math><msub><mrow><mi>p</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>p</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span>. We conjecture that there exists <span><math><mi>x</mi><mo>∈</mo><mi>G</mi></math></span> such that <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∩</mo><msubsup><mrow><mi>P</mi></mrow><mrow><mi>i</mi></mrow><mrow><mi>x</mi></mrow></msubsup></math></span> is inclusion-minimal in <span><math><mo>{</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∩</mo><msubsup><mrow><mi>P</mi></mrow><mrow><mi>i</mi></mrow><mrow><mi>g</mi></mrow></msubsup><mo>:</mo><mi>g</mi><mo>∈</mo><mi>G</mi><mo>}</mo></math></span> for all <em>i</em>. As a first step in this direction, we show that a finite group cannot be covered by (proper) Sylow normalizers for distinct primes. Then we settle the conjecture in two opposite situations: symmetric and alternating groups of large degree and metanilpotent groups of odd order. Applications concerning the intersections of nilpotent subgroups are discussed.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 824-837"},"PeriodicalIF":0.8,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170546","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 : 2026-01-27DOI: 10.1016/j.jalgebra.2026.01.022
Thu T.H. Quan, Hung P. Tong-Viet
In this paper, we investigate certain generalizations of Camina pairs. Let H be a nontrivial proper subgroup of a finite group G. We first show that every nontrivial irreducible complex character of H induces homogeneously to G if and only if for every , the element x is conjugate to xh for all . Furthermore we prove that if xh is conjugate to either x or for all and all , then the normal closure N of H in G also satisfies the same condition, and N is nilpotent. Finally, we determine the structure of H under the assumption that for every element of odd order, the coset xH consists entirely of elements of odd order.
{"title":"Some generalizations of Camina pairs and orders of elements in cosets","authors":"Thu T.H. Quan, Hung P. Tong-Viet","doi":"10.1016/j.jalgebra.2026.01.022","DOIUrl":"10.1016/j.jalgebra.2026.01.022","url":null,"abstract":"<div><div>In this paper, we investigate certain generalizations of Camina pairs. Let <em>H</em> be a nontrivial proper subgroup of a finite group <em>G</em>. We first show that every nontrivial irreducible complex character of <em>H</em> induces homogeneously to <em>G</em> if and only if for every <span><math><mi>x</mi><mo>∈</mo><mi>G</mi><mo>∖</mo><mi>H</mi></math></span>, the element <em>x</em> is conjugate to <em>xh</em> for all <span><math><mi>h</mi><mo>∈</mo><mi>H</mi></math></span>. Furthermore we prove that if <em>xh</em> is conjugate to either <em>x</em> or <span><math><msup><mrow><mi>x</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> for all <span><math><mi>h</mi><mo>∈</mo><mi>H</mi></math></span> and all <span><math><mi>x</mi><mo>∈</mo><mi>G</mi><mo>∖</mo><mi>H</mi></math></span>, then the normal closure <em>N</em> of <em>H</em> in <em>G</em> also satisfies the same condition, and <em>N</em> is nilpotent. Finally, we determine the structure of <em>H</em> under the assumption that for every element <span><math><mi>x</mi><mo>∈</mo><mi>G</mi><mo>∖</mo><mi>H</mi></math></span> of odd order, the coset <em>xH</em> consists entirely of elements of odd order.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 838-862"},"PeriodicalIF":0.8,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170547","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 : 2026-01-22DOI: 10.1016/j.jalgebra.2026.01.014
Joris van der Hoeven, Gleb Pogudin
Recently, Kauers, Koutschan, and Verron proved a non-commutative version of the classical shape lemma in the theory of Gröbner bases. Their result requires the ideal to be D-radical. In this note, we prove a new non-commutative shape lemma that does not require this assumption.
{"title":"Yet another differential shape lemma","authors":"Joris van der Hoeven, Gleb Pogudin","doi":"10.1016/j.jalgebra.2026.01.014","DOIUrl":"10.1016/j.jalgebra.2026.01.014","url":null,"abstract":"<div><div>Recently, Kauers, Koutschan, and Verron proved a non-commutative version of the classical shape lemma in the theory of Gröbner bases. Their result requires the ideal to be D-radical. In this note, we prove a new non-commutative shape lemma that does not require this assumption.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 683-689"},"PeriodicalIF":0.8,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075488","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 : 2026-01-21DOI: 10.1016/j.jalgebra.2026.01.003
Jinjin Liang, Wen Chen, Erxiao Wang
We develop the basic and new tools for classifying non-side-to-side tilings of the sphere by congruent triangles. Then we prove that, if the triangle has any irrational angle in degree, such tilings are: a sequence of 1-parameter families of triangles each admitting many 2-layer earth map tilings with 2n() tiles, together with rotational modifications for even n; a 1-parameter family of triangles each admitting a unique tiling with 8 tiles; and a sporadic triangle admitting a unique tiling with 16 tiles. Then a scheme is outlined to classify the case with all angles being rational in degree, justified by some known and new examples.
{"title":"Non-side-to-side tilings of the sphere by congruent triangles with an irrational angle","authors":"Jinjin Liang, Wen Chen, Erxiao Wang","doi":"10.1016/j.jalgebra.2026.01.003","DOIUrl":"10.1016/j.jalgebra.2026.01.003","url":null,"abstract":"<div><div>We develop the basic and new tools for classifying non-side-to-side tilings of the sphere by congruent triangles. Then we prove that, if the triangle has any irrational angle in degree, such tilings are: a sequence of 1-parameter families of triangles each admitting many 2-layer earth map tilings with 2<em>n</em>(<span><math><mi>n</mi><mo>≥</mo><mn>3</mn></math></span>) tiles, together with rotational modifications for even <em>n</em>; a 1-parameter family of triangles each admitting a unique tiling with 8 tiles; and a sporadic triangle admitting a unique tiling with 16 tiles. Then a scheme is outlined to classify the case with all angles being rational in degree, justified by some known and new examples.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 587-610"},"PeriodicalIF":0.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075490","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 : 2026-01-21DOI: 10.1016/j.jalgebra.2026.01.020
Sheela Devadas
The global analogue of a Henselian local ring is a Henselian pair: a ring A and an ideal I which satisfy a condition resembling Hensel's lemma regarding lifting coprime factorizations of polynomials over to factorizations over A. The geometric counterpart is the notion of a Henselian scheme, which is an analogue of a tubular neighborhood in algebraic geometry.
In this paper we revisit the foundations of the theory of Henselian schemes. The pathological behavior of quasi-coherent sheaves on Henselian schemes in characteristic 0 makes them poor models for an “algebraic tube” in characteristic 0. We show that such problems do not arise in positive characteristic, and establish good properties for analogues of smooth and étale maps in the general Henselian setting.
{"title":"Henselian schemes in positive characteristic","authors":"Sheela Devadas","doi":"10.1016/j.jalgebra.2026.01.020","DOIUrl":"10.1016/j.jalgebra.2026.01.020","url":null,"abstract":"<div><div>The global analogue of a Henselian local ring is a Henselian pair: a ring <em>A</em> and an ideal <em>I</em> which satisfy a condition resembling Hensel's lemma regarding lifting coprime factorizations of polynomials over <span><math><mi>A</mi><mo>/</mo><mi>I</mi></math></span> to factorizations over <em>A</em>. The geometric counterpart is the notion of a Henselian scheme, which is an analogue of a tubular neighborhood in algebraic geometry.</div><div>In this paper we revisit the foundations of the theory of Henselian schemes. The pathological behavior of quasi-coherent sheaves on Henselian schemes in characteristic 0 makes them poor models for an “algebraic tube” in characteristic 0. We show that such problems do not arise in positive characteristic, and establish good properties for analogues of smooth and étale maps in the general Henselian setting.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 531-586"},"PeriodicalIF":0.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025646","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 : 2026-01-21DOI: 10.1016/j.jalgebra.2025.12.023
Filippo Ambrosio , Andrea Santi
Let be a periodically graded semisimple complex Lie algebra. In this note, we give a uniform proof of the recent result by W. de Graaf and H. V. Lê that the hyperplane arrangement determined by the restrictions of the roots of to a Cartan subspace coincides with the hyperplane arrangement of (complex) reflections of the little Weyl group of .
设g= φ i∈Z/mZgi是一个周期渐变的半简单复李代数。在本文中,我们统一证明了W. de Graaf和H. V. Lê最近的结果,即由g的根对Cartan子空间c∧g1的限制所决定的超平面排列与g= i∈Z/mZgi的小Weyl群的(复)反射的超平面排列是一致的。
{"title":"Hyperplane arrangements and Vinberg's θ-groups","authors":"Filippo Ambrosio , Andrea Santi","doi":"10.1016/j.jalgebra.2025.12.023","DOIUrl":"10.1016/j.jalgebra.2025.12.023","url":null,"abstract":"<div><div>Let <span><math><mi>g</mi><mo>=</mo><msub><mrow><mo>⨁</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>Z</mi><mo>/</mo><mi>m</mi><mi>Z</mi></mrow></msub><msub><mrow><mi>g</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> be a periodically graded semisimple complex Lie algebra. In this note, we give a uniform proof of the recent result by W. de Graaf and H. V. Lê that the hyperplane arrangement determined by the restrictions of the roots of <span><math><mi>g</mi></math></span> to a Cartan subspace <span><math><mi>c</mi><mo>⊂</mo><msub><mrow><mi>g</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> coincides with the hyperplane arrangement of (complex) reflections of the little Weyl group of <span><math><mi>g</mi><mo>=</mo><msub><mrow><mo>⨁</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>Z</mi><mo>/</mo><mi>m</mi><mi>Z</mi></mrow></msub><msub><mrow><mi>g</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 770-789"},"PeriodicalIF":0.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075559","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 : 2026-01-21DOI: 10.1016/j.jalgebra.2026.01.006
Satyabrat Sahoo
Let K be a totally real number field and be the ring of integers of K. In this article, we study the asymptotic solutions of the generalized Fermat equation, namely over K with prime exponent p, where with ABC is even. For certain class of fields K, we prove that the equation has no asymptotic solution with . Then, under some assumptions on , we also prove that has no asymptotic solution in . Finally, we give several purely local criteria of K such that has no asymptotic solutions in , and calculate the density of such fields K when K is a real quadratic field.
{"title":"On the solutions of the generalized Fermat equation over totally real number fields","authors":"Satyabrat Sahoo","doi":"10.1016/j.jalgebra.2026.01.006","DOIUrl":"10.1016/j.jalgebra.2026.01.006","url":null,"abstract":"<div><div>Let <em>K</em> be a totally real number field and <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>K</mi></mrow></msub></math></span> be the ring of integers of <em>K</em>. In this article, we study the asymptotic solutions of the generalized Fermat equation, namely <span><math><mi>A</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>B</mi><msup><mrow><mi>y</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>C</mi><msup><mrow><mi>z</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>=</mo><mn>0</mn></math></span> over <em>K</em> with prime exponent <em>p</em>, where <span><math><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>∈</mo><msub><mrow><mi>O</mi></mrow><mrow><mi>K</mi></mrow></msub><mo>∖</mo><mo>{</mo><mn>0</mn><mo>}</mo></math></span> with <em>ABC</em> is even. For certain class of fields <em>K</em>, we prove that the equation <span><math><mi>A</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>B</mi><msup><mrow><mi>y</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>C</mi><msup><mrow><mi>z</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>=</mo><mn>0</mn></math></span> has no asymptotic solution <span><math><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo><mo>∈</mo><msubsup><mrow><mi>O</mi></mrow><mrow><mi>K</mi></mrow><mrow><mn>3</mn></mrow></msubsup></math></span> with <span><math><mn>2</mn><mo>|</mo><mi>a</mi><mi>b</mi><mi>c</mi></math></span>. Then, under some assumptions on <span><math><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi></math></span>, we also prove that <span><math><mi>A</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>B</mi><msup><mrow><mi>y</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>C</mi><msup><mrow><mi>z</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>=</mo><mn>0</mn></math></span> has no asymptotic solution in <span><math><msup><mrow><mi>K</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>. Finally, we give several purely local criteria of <em>K</em> such that <span><math><mi>A</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>B</mi><msup><mrow><mi>y</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>C</mi><msup><mrow><mi>z</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>=</mo><mn>0</mn></math></span> has no asymptotic solutions in <span><math><msup><mrow><mi>K</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>, and calculate the density of such fields <em>K</em> when <em>K</em> is a real quadratic field.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"693 ","pages":"Pages 690-709"},"PeriodicalIF":0.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075493","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}