Bulletin of the London Mathematical Society最新文献

{"title":"Erratum: Symplectic involutions of \u0000 \u0000 \u0000 K\u0000 \u0000 3\u0000 \u0000 [\u0000 n\u0000 ]\u0000 \u0000 \u0000 \u0000 $K3^{[n]}$\u0000 type and Kummer n type manifolds","authors":"Ljudmila Kamenova,&nbsp;Giovanni Mongardi,&nbsp;Alexei Oblomkov","doi":"10.1112/blms.70128","DOIUrl":"https://doi.org/10.1112/blms.70128","url":null,"abstract":"<p>In this note, we present a corrected formula for the enumeration of connected components of the locus fixed by a symplectic involution inside hyperkähler manifolds of types <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>K</mi>\u0000 <msup>\u0000 <mn>3</mn>\u0000 <mrow>\u0000 <mo>[</mo>\u0000 <mi>n</mi>\u0000 <mo>]</mo>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$K3^{[n]}$</annotation>\u0000 </semantics></math> and generalized Kummer. We also provide further precisions concerning the involutions considered in the Kummer case.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2235-2237"},"PeriodicalIF":0.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70128","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum: Graph bundles and Ricci-flatness","authors":"Wenbo Li,&nbsp;Shiping Liu","doi":"10.1112/blms.70111","DOIUrl":"https://doi.org/10.1112/blms.70111","url":null,"abstract":"<p>This note is a corrigendum to the authors' paper “Graph bundles and Ricci–flatness, Bulletin of the London Mathematical Society, 56(2), pp. 523–535, 2024”.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 6","pages":"1921-1922"},"PeriodicalIF":0.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144245168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual matroids of 2-complexes — Revisited","authors":"Johannes Carmesin","doi":"10.1112/blms.70077","DOIUrl":"https://doi.org/10.1112/blms.70077","url":null,"abstract":"<p>We prove that simply connected local two-dimensional simplicial complexes embed in 3-space if and only if their dual matroids are graphic. Examples are provided that the assumptions of simply connectedness and locality are necessary. This may be regarded as a three-dimensional analogue of Whitney's planarity criterion from 1932.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2033-2044"},"PeriodicalIF":0.8,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the stack of 0-dimensional coherent sheaves: Motivic aspects","authors":"Barbara Fantechi,&nbsp;Andrea T. Ricolfi","doi":"10.1112/blms.70096","DOIUrl":"https://doi.org/10.1112/blms.70096","url":null,"abstract":"&lt;p&gt;Let &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;annotation&gt;$X$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; be a variety. In this survey, we study (decompositions of) the motivic class, in the Grothendieck ring of stacks, of the stack &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;o&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;h&lt;/mi&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$mathcal {C}hspace{-2.5pt}{o}hspace{-1.99997pt}{h}^n(X)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; of 0-dimensional coherent sheaves of length &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;annotation&gt;$n$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; on &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;annotation&gt;$X$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. To do so, we review the construction of the support map &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;o&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;h&lt;/mi&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;→&lt;/mo&gt;\u0000 &lt;msup&gt;\u0000 &lt;mo&gt;Sym&lt;/mo&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$mathcal {C}hspace{-2.5pt}{o}hspace{-1.99997pt}{h}^n(X) rightarrow operatorname{Sym}^n(X)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; to the symmetric product and we prove that, for any closed point &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;mo&gt;∈&lt;/mo&gt;\u0000 &lt;mi&gt;X&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$p in X$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, the motive of the punctual stack &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mi&gt;o&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;h&lt;/mi&gt;\u0000 &lt;mi&gt;n&lt;/mi&gt;\u0000 &lt;/msup&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 ","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 6","pages":"1607-1649"},"PeriodicalIF":0.8,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144245008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the boundary criterion for relative cubulation: Multiended parabolics","authors":"Eduard Einstein,&nbsp;Suraj Krishna M S,&nbsp;Thomas Ng","doi":"10.1112/blms.70087","DOIUrl":"https://doi.org/10.1112/blms.70087","url":null,"abstract":"<p>In this note, we extend the boundary criterion for relative cubulation of the first author and Groves to the case when the peripheral subgroups are not necessarily one-ended. Specifically, if the boundary criterion is satisfied for a relatively hyperbolic group, we show that, up to taking a <i>refined peripheral structure</i>, the group admits a relatively geometric action on a CAT(0) cube complex. We anticipate that this refinement will be useful for constructing new relative cubulations in a variety of settings.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2177-2189"},"PeriodicalIF":0.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144680994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hilbert–Kunz multiplicity of powers of ideals in dimension two","authors":"Alessandro De Stefani,&nbsp;Shreedevi K. Masuti,&nbsp;Maria Evelina Rossi,&nbsp;Jugal K. Verma","doi":"10.1112/blms.70086","DOIUrl":"https://doi.org/10.1112/blms.70086","url":null,"abstract":"<p>We study the behavior of the Hilbert–Kunz multiplicity of powers of an ideal in a local ring. In dimension 2, we provide answers to some problems raised by Smirnov, and give a criterion to answer one of his questions in terms of a “Ratliff–Rush version” of the Hilbert–Kunz multiplicity.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2155-2176"},"PeriodicalIF":0.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Presentation of kernels of rational characters of right-angled Artin groups","authors":"Montserrat Casals-Ruiz,&nbsp;Ilya Kazachkov,&nbsp;Mallika Roy","doi":"10.1112/blms.70090","DOIUrl":"https://doi.org/10.1112/blms.70090","url":null,"abstract":"<p>In this note, we characterise when the kernel of a rational character of a right-angled Artin group, also known as generalised Bestiva–Brady group, is finitely generated and finitely presented. In these cases, we exhibit a finite generating set and a presentation. These results generalise Dicks and Leary's presentations of Bestiva–Brady kernels and provide an algebraic proof for the results proven by Meier, Meinert and VanWyk.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2219-2234"},"PeriodicalIF":0.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70090","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Double star arrangement and the pointed multinet","authors":"Yongqiang Liu,&nbsp;Wentao Xie","doi":"10.1112/blms.70089","DOIUrl":"https://doi.org/10.1112/blms.70089","url":null,"abstract":"<p>Let <span></span><math>\u0000 <semantics>\u0000 <mi>A</mi>\u0000 <annotation>$mathcal {A}$</annotation>\u0000 </semantics></math> be a hyperplane arrangement in a complex projective space. It is an open question if the degree one cohomology jump loci (with complex coefficients) are determined by the combinatorics of <span></span><math>\u0000 <semantics>\u0000 <mi>A</mi>\u0000 <annotation>$mathcal {A}$</annotation>\u0000 </semantics></math>. By the work of Falk and Yuzvinsky [Compositio Math. 143 (2007), no. 4, 1069–1088] and Marco-Buzunáriz [Graphs Combin. 25 (2009), no. 4, 469–488], all the irreducible components passing through the origin are determined by the multinet structure, which is combinatorially determined. Denham and Suciu introduced the pointed multinet structure, which is combinatorially determined, to obtain examples of arrangements with translated positive-dimensional components in the degree one cohomology jump loci [Proc. Lond. Math. Soc. (3) 108 (2014), no. 6, 1435–1470]. Suciu asked the question if all translated positive-dimensional components appear in this manner [Ann. Fac. Sci. Toulouse Math. (6) 23 (2014), no. 2, 417–481]. In this paper, we show that the double star arrangement introduced by Ishibashi, Sugawara, and Yoshinaga [Adv. in Appl. Math. 162 (2025), Paper No. 102790, Example 3.2] gives a negative answer to this question.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2210-2218"},"PeriodicalIF":0.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Étale motives of geometric origin","authors":"Raphaël Ruimy,&nbsp;Swann Tubach","doi":"10.1112/blms.70085","DOIUrl":"https://doi.org/10.1112/blms.70085","url":null,"abstract":"<p>Over qcqs finite-dimensional schemes, we prove that étale motives of geometric origin can be characterised by a constructibility property which is purely categorical, giving a full answer to the question ‘Do all constructible étale motives come from geometry?’ which dates back to Cisinski and Déglise's work. We also show that they afford the continuity property and satisfy h-descent and Milnor excision.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2116-2131"},"PeriodicalIF":0.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-intersections of arcs on a pair of pants","authors":"Nhat Minh Doan,&nbsp;Hanh Vo","doi":"10.1112/blms.70088","DOIUrl":"https://doi.org/10.1112/blms.70088","url":null,"abstract":"<p>We investigate arcs on a pair of pants and present an algorithm to compute the self-intersection number of an arc. Additionally, we establish bounds for the self-intersection number in terms of the word length. We also prove that the spectrum of self-intersection numbers of 2-low-lying arcs covers all natural numbers.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"2190-2209"},"PeriodicalIF":0.8,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}