Yuri Bilu, Florian Luca, Joris Nieuwveld, Joël Ouaknine, James Worrell
{"title":"Twisted rational zeros of linear recurrence sequences","authors":"Yuri Bilu, Florian Luca, Joris Nieuwveld, Joël Ouaknine, James Worrell","doi":"10.1112/jlms.70126","DOIUrl":"https://doi.org/10.1112/jlms.70126","url":null,"abstract":"<p>We introduce the notion of a twisted rational zero of a nondegenerate linear recurrence sequence (LRS). We show that any nondegenerate LRS has only finitely many such twisted rational zeros. In the particular case of the Tribonacci sequence, we show that <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>1</mn>\u0000 <mo>/</mo>\u0000 <mn>3</mn>\u0000 </mrow>\u0000 <annotation>$1/3$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>5</mn>\u0000 <mo>/</mo>\u0000 <mn>3</mn>\u0000 </mrow>\u0000 <annotation>$-5/3$</annotation>\u0000 </semantics></math> are the only twisted rational zeros that are not integral zeros.</p>","PeriodicalId":49989,"journal":{"name":"Journal of the London Mathematical Society-Second Series","volume":"111 3","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/jlms.70126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Lipschitz decompositions of domains with bilaterally flat boundaries","authors":"Jared Krandel","doi":"10.1112/jlms.70128","DOIUrl":"https://doi.org/10.1112/jlms.70128","url":null,"abstract":"<p>We study classes of domains in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mrow>\u0000 <mi>d</mi>\u0000 <mo>+</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 <mo>,</mo>\u0000 <mspace></mspace>\u0000 <mi>d</mi>\u0000 <mo>⩾</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 <annotation>$mathbb {R}^{d+1}, d geqslant 2$</annotation>\u0000 </semantics></math> with sufficiently flat boundaries that admit a decomposition or covering of bounded overlap by Lipschitz graph domains with controlled total surface area. This study is motivated by the following result proved by Peter Jones as a piece of his proof of the Analyst's Traveling Salesman Theorem in the complex plane: Any simply connected domain <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Ω</mi>\u0000 <mo>⊆</mo>\u0000 <mi>C</mi>\u0000 </mrow>\u0000 <annotation>$Omega subseteq mathbb {C}$</annotation>\u0000 </semantics></math> with finite boundary length <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>H</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mi>∂</mi>\u0000 <mi>Ω</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <mo><</mo>\u0000 <mi>∞</mi>\u0000 </mrow>\u0000 <annotation>$mathcal {H}^1(partial Omega) < infty$</annotation>\u0000 </semantics></math> can be decomposed into Lipschitz graph domains with total boundary length at most <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>M</mi>\u0000 <msup>\u0000 <mi>H</mi>\u0000 <mn>1</mn>\u0000 </msup>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mi>∂</mi>\u0000 <mi>Ω</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation>$Mmathcal {H}^1(partial Omega)$</annotation>\u0000 </semantics></math> for some <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>M</mi>\u0000 <mo>></mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$M > 0$</annotation>\u0000 </semantics></math> independent of <span></span><math>\u0000 <semantics>\u0000 <mi>Ω</mi>\u0000 ","PeriodicalId":49989,"journal":{"name":"Journal of the London Mathematical Society-Second Series","volume":"111 3","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/jlms.70128","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A presentation of the torus-equivariant quantum \u0000 \u0000 K\u0000 $K$\u0000 -theory ring of flag manifolds of type \u0000 \u0000 A\u0000 $A$\u0000 , Part I: The defining ideal","authors":"Toshiaki Maeno, Satoshi Naito, Daisuke Sagaki","doi":"10.1112/jlms.70095","DOIUrl":"https://doi.org/10.1112/jlms.70095","url":null,"abstract":"<p>We give a presentation of the torus-equivariant (small) quantum <span></span><math>\u0000 <semantics>\u0000 <mi>K</mi>\u0000 <annotation>$K$</annotation>\u0000 </semantics></math>-theory ring of flag manifolds of type <span></span><math>\u0000 <semantics>\u0000 <mi>A</mi>\u0000 <annotation>$A$</annotation>\u0000 </semantics></math>, as the quotient of a polynomial ring by an explicit ideal. This result is the torus-equivariant version of our previous one, which gives a presentation of the nonequivariant quantum <span></span><math>\u0000 <semantics>\u0000 <mi>K</mi>\u0000 <annotation>$K$</annotation>\u0000 </semantics></math>-theory ring of flag manifolds of type <span></span><math>\u0000 <semantics>\u0000 <mi>A</mi>\u0000 <annotation>$A$</annotation>\u0000 </semantics></math>. However, the method of proof for the torus-equivariant one is entirely different from that for the nonequivariant one; our proof is based on the result in the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Q</mi>\u0000 <mo>=</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$Q = 0$</annotation>\u0000 </semantics></math> limit, and uses Nakayama-type arguments to upgrade it to the quantum situation. Also, in contrast to the nonequivariant case in which we used the Chevalley formula, we make use of the inverse Chevalley formula for the torus-equivariant <span></span><math>\u0000 <semantics>\u0000 <mi>K</mi>\u0000 <annotation>$K$</annotation>\u0000 </semantics></math>-group of semi-infinite flag manifolds to obtain relations that yield our presentation.</p>","PeriodicalId":49989,"journal":{"name":"Journal of the London Mathematical Society-Second Series","volume":"111 3","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689171","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}