{"title":"New s-number classes and summing classes of bilinear operators","authors":"Eduardo Brandani da Silva, Dicesar Lass Fernandez","doi":"10.1007/s43034-025-00464-y","DOIUrl":null,"url":null,"abstract":"<div><p>We introduce classes of bilinear operators of <span>\\(\\ell _{p,q}\\)</span>-type, i.e. classes of operators in which their sequences of s-numbers are in <span>\\(\\ell _{p,q},\\)</span> and their properties and relationships are studied. We also introduce two classes of summing bilinear operators: the class <span>\\(\\Pi _{p,q;r}^{ss}\\)</span> of strongly summing operators, and the class <span>\\(\\Pi _{p,q;r,s}^{as}\\)</span> of absolutely summing operators. These classes share some properties with similar proofs. But, some others properties are specific for one or the other class. Also, they are somewhat more general than the multilinear summing classes introduced before by several authors. Relationships between classes of <span>\\(\\ell _{p,q}\\)</span>-type and summing classes are given.</p></div>","PeriodicalId":48858,"journal":{"name":"Annals of Functional Analysis","volume":"16 4","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annals of Functional Analysis","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s43034-025-00464-y","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
We introduce classes of bilinear operators of \(\ell _{p,q}\)-type, i.e. classes of operators in which their sequences of s-numbers are in \(\ell _{p,q},\) and their properties and relationships are studied. We also introduce two classes of summing bilinear operators: the class \(\Pi _{p,q;r}^{ss}\) of strongly summing operators, and the class \(\Pi _{p,q;r,s}^{as}\) of absolutely summing operators. These classes share some properties with similar proofs. But, some others properties are specific for one or the other class. Also, they are somewhat more general than the multilinear summing classes introduced before by several authors. Relationships between classes of \(\ell _{p,q}\)-type and summing classes are given.
期刊介绍:
Annals of Functional Analysis is published by Birkhäuser on behalf of the Tusi Mathematical Research Group.
Ann. Funct. Anal. is a peer-reviewed electronic journal publishing papers of high standards with deep results, new ideas, profound impact, and significant implications in all areas of functional analysis and all modern related topics (e.g., operator theory). Ann. Funct. Anal. normally publishes original research papers numbering 18 or fewer pages in the journal’s style. Longer papers may be submitted to the Banach Journal of Mathematical Analysis or Advances in Operator Theory.
Ann. Funct. Anal. presents the best paper award yearly. The award in the year n is given to the best paper published in the years n-1 and n-2. The referee committee consists of selected editors of the journal.