{"title":"Fractional Laplacian in V-shaped waveguide","authors":"Fedor Bakharev, Sergey Matveenko","doi":"10.1002/mana.202400271","DOIUrl":"https://doi.org/10.1002/mana.202400271","url":null,"abstract":"<p>The spectral properties of the restricted fractional Dirichlet Laplacian in <span>V</span>-shaped waveguides are studied. The continuous spectrum for such domains with cylindrical outlets is known to occupy the ray <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>[</mo>\u0000 <msub>\u0000 <mi>Λ</mi>\u0000 <mo>†</mo>\u0000 </msub>\u0000 <mo>,</mo>\u0000 <mo>+</mo>\u0000 <mi>∞</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$[Lambda _dagger, +infty)$</annotation>\u0000 </semantics></math> with the threshold corresponding to the smallest eigenvalue of the cross-sectional problems. In this work, the presence of a discrete spectrum at any junction angle is established along with the monotonic dependence of the discrete spectrum on the angle.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 2","pages":"427-436"},"PeriodicalIF":0.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397039","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":"Infinitely many low- and high-energy solutions for double-phase problems with variable exponent","authors":"Chun-Bo Lian, Qing-Hai Cao, Bin Ge","doi":"10.1002/mana.202300284","DOIUrl":"https://doi.org/10.1002/mana.202300284","url":null,"abstract":"<p>The aim of this paper is the study of double-phase problems with variable exponent. Using the Clark's theorem and the symmetric mountain pass lemma, we prove the existence of infinitely many small solutions and infinitely many large solutions, respectively.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 1","pages":"142-155"},"PeriodicalIF":0.8,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114308","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":"Multi-bump solutions for the nonlinear magnetic Schrödinger equation with logarithmic nonlinearity","authors":"Jun Wang, Zhaoyang Yin","doi":"10.1002/mana.202400134","DOIUrl":"https://doi.org/10.1002/mana.202400134","url":null,"abstract":"<p>In this paper, we study the following nonlinear magnetic Schrödinger equation with logarithmic nonlinearity\u0000\u0000 </p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 1","pages":"328-355"},"PeriodicalIF":0.8,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114307","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":"Realization of finite groups as isometry groups and problems of minimality","authors":"Pedro J. Chocano","doi":"10.1002/mana.202400287","DOIUrl":"https://doi.org/10.1002/mana.202400287","url":null,"abstract":"<p>A finite group <span></span><math>\u0000 <semantics>\u0000 <mi>G</mi>\u0000 <annotation>$G$</annotation>\u0000 </semantics></math> is said to be realized by a finite subset <span></span><math>\u0000 <semantics>\u0000 <mi>V</mi>\u0000 <annotation>$V$</annotation>\u0000 </semantics></math> of a Euclidean space <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mi>n</mi>\u0000 </msup>\u0000 <annotation>$mathbb {R}^n$</annotation>\u0000 </semantics></math> if the isometry group of <span></span><math>\u0000 <semantics>\u0000 <mi>V</mi>\u0000 <annotation>$V$</annotation>\u0000 </semantics></math> is isomorphic to <span></span><math>\u0000 <semantics>\u0000 <mi>G</mi>\u0000 <annotation>$G$</annotation>\u0000 </semantics></math>. We prove that every finite group can be realized by a finite subset <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>V</mi>\u0000 <mo>⊂</mo>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mrow>\u0000 <mo>|</mo>\u0000 <mi>G</mi>\u0000 <mo>|</mo>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$Vsubset mathbb {R}^{|G|}$</annotation>\u0000 </semantics></math> consisting of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mo>|</mo>\u0000 <mi>G</mi>\u0000 <mo>|</mo>\u0000 <mo>(</mo>\u0000 <mo>|</mo>\u0000 <mi>S</mi>\u0000 <mo>|</mo>\u0000 </mrow>\u0000 <mo>+</mo>\u0000 <mrow>\u0000 <mn>1</mn>\u0000 <mo>)</mo>\u0000 <mo>(</mo>\u0000 </mrow>\u0000 <mo>≤</mo>\u0000 <mrow>\u0000 <mo>|</mo>\u0000 <mi>G</mi>\u0000 <mo>|</mo>\u0000 <mo>(</mo>\u0000 </mrow>\u0000 <msub>\u0000 <mi>log</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mo>|</mo>\u0000 <mi>G</mi>\u0000 <mo>|</mo>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <mo>+</mo>\u0000 <mrow>\u0000 <mn>1</mn>\u0000 <mo>)</mo>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 2","pages":"419-426"},"PeriodicalIF":0.8,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mana.202400287","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396770","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}
Filippo De Mari, Matteo Levi, Matteo Monti, Maria Vallarino
{"title":"Calderón–Zygmund theory on some Lie groups of exponential growth","authors":"Filippo De Mari, Matteo Levi, Matteo Monti, Maria Vallarino","doi":"10.1002/mana.202300499","DOIUrl":"https://doi.org/10.1002/mana.202300499","url":null,"abstract":"<p>Let <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>G</mi>\u0000 <mo>=</mo>\u0000 <mi>N</mi>\u0000 <mo>⋊</mo>\u0000 <mi>A</mi>\u0000 </mrow>\u0000 <annotation>$G = N rtimes A$</annotation>\u0000 </semantics></math>, where <span></span><math>\u0000 <semantics>\u0000 <mi>N</mi>\u0000 <annotation>$N$</annotation>\u0000 </semantics></math> is a stratified Lie group and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>A</mi>\u0000 <mo>=</mo>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mo>+</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$A= mathbb {R}_+$</annotation>\u0000 </semantics></math> acts on <span></span><math>\u0000 <semantics>\u0000 <mi>N</mi>\u0000 <annotation>$N$</annotation>\u0000 </semantics></math> via automorphic dilations. We prove that the group <span></span><math>\u0000 <semantics>\u0000 <mi>G</mi>\u0000 <annotation>$G$</annotation>\u0000 </semantics></math> has the Calderón–Zygmund property, in the sense of Hebisch and Steger, with respect to a family of flow measures and metrics. This generalizes in various directions previous works by Hebisch and Steger and Martini et al., and provides a new approach in the development of the Calderón–Zygmund theory in Lie groups of exponential growth. We also prove a weak-type (1,1) estimate for the Hardy–Littlewood maximal operator naturally arising in this setting.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 1","pages":"113-141"},"PeriodicalIF":0.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mana.202300499","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111990","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}
Geraldo Botelho, Luis Alberto Garcia, Vinícius C. C. Miranda
{"title":"Disjoint \u0000 \u0000 p\u0000 $p$\u0000 -convergent operators and their adjoints","authors":"Geraldo Botelho, Luis Alberto Garcia, Vinícius C. C. Miranda","doi":"10.1002/mana.202300561","DOIUrl":"https://doi.org/10.1002/mana.202300561","url":null,"abstract":"<p>First, we give conditions on a Banach lattice <span></span><math>\u0000 <semantics>\u0000 <mi>E</mi>\u0000 <annotation>$E$</annotation>\u0000 </semantics></math> so that an operator <span></span><math>\u0000 <semantics>\u0000 <mi>T</mi>\u0000 <annotation>$T$</annotation>\u0000 </semantics></math> from <span></span><math>\u0000 <semantics>\u0000 <mi>E</mi>\u0000 <annotation>$E$</annotation>\u0000 </semantics></math> to any Banach space is disjoint <span></span><math>\u0000 <semantics>\u0000 <mi>p</mi>\u0000 <annotation>$p$</annotation>\u0000 </semantics></math>-convergent if and only if <span></span><math>\u0000 <semantics>\u0000 <mi>T</mi>\u0000 <annotation>$T$</annotation>\u0000 </semantics></math> is almost Dunford–Pettis. Then, we study when adjoints of positive operators between Banach lattices are disjoint <span></span><math>\u0000 <semantics>\u0000 <mi>p</mi>\u0000 <annotation>$p$</annotation>\u0000 </semantics></math>-convergent. For instance, we prove that the following conditions are equivalent for all Banach lattices <span></span><math>\u0000 <semantics>\u0000 <mi>E</mi>\u0000 <annotation>$E$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mi>F</mi>\u0000 <annotation>$F$</annotation>\u0000 </semantics></math>: (i) a positive operator <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>T</mi>\u0000 <mo>:</mo>\u0000 <mi>E</mi>\u0000 <mo>→</mo>\u0000 <mi>F</mi>\u0000 </mrow>\u0000 <annotation>$T: E rightarrow F$</annotation>\u0000 </semantics></math> is almost weak <span></span><math>\u0000 <semantics>\u0000 <mi>p</mi>\u0000 <annotation>$p$</annotation>\u0000 </semantics></math>-convergent if and only if <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>T</mi>\u0000 <mo>∗</mo>\u0000 </msup>\u0000 <annotation>$T^*$</annotation>\u0000 </semantics></math> is disjoint <span></span><math>\u0000 <semantics>\u0000 <mi>p</mi>\u0000 <annotation>$p$</annotation>\u0000 </semantics></math>-convergent; (ii) <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>E</mi>\u0000 <mo>∗</mo>\u0000 </msup>\u0000 <annotation>$E^*$</annotation>\u0000 </semantics></math> has order continuous norm or <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>F</mi>\u0000 <mo>∗</mo>\u0000 </msup>\u0000 <annotation>$F^*$</annotation>\u0000 </semantics></math> has the positive Schur property of order <span></span><math>\u0000","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"297 12","pages":"4766-4777"},"PeriodicalIF":0.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862177","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}