{"title":"On the Lyapunov exponents of triangular discrete time-varying systems","authors":"Adam Czornik, Thai Son Doan","doi":"10.1002/mana.202300373","DOIUrl":"https://doi.org/10.1002/mana.202300373","url":null,"abstract":"<p>In this paper, we present upper and lower estimates for the Lyapunov exponents of discrete linear systems with triangular time-varying coefficients. These estimates are expressed by the diagonal elements of the coefficient matrix. As a conclusion from these estimates, we also obtain bounds for the Grobman regularity coefficient.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 3","pages":"976-997"},"PeriodicalIF":0.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595337","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":"Rational cohomology of \u0000 \u0000 \u0000 M\u0000 \u0000 4\u0000 ,\u0000 1\u0000 \u0000 \u0000 $mathcal {M}_{4,1}$","authors":"Yiu Man Wong, Angelina Zheng","doi":"10.1002/mana.202400294","DOIUrl":"https://doi.org/10.1002/mana.202400294","url":null,"abstract":"<p>We compute the rational cohomology of the moduli space <span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mrow>\u0000 <mn>4</mn>\u0000 <mo>,</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msub>\u0000 <annotation>$mathcal {M}_{4,1}$</annotation>\u0000 </semantics></math> of nonsingular genus 4 curves with one marked point, using Gorinov–Vassiliev's method.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 3","pages":"1041-1061"},"PeriodicalIF":0.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mana.202400294","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595435","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}