{"title":"First module cohomology group of induced semigroup algebras","authors":"M. Miri, E. Nasrabadi, Kianoush Kazemi","doi":"10.5269/bspm.51414","DOIUrl":null,"url":null,"abstract":"Let $S$ be a discrete semigroup and $T$ be a left multiplier operator on $S$. A new product on $S$ defined by $T$ creates a new induced semigroup $S _{T} $. In this paper, we show that if $T$ is bijective, then the first module cohomology groups $ \\HH_{\\ell^1(E)}^{1}(\\ell^1(S), \\ell^{\\infty}(S))$ and $ \\HH_{\\ell^1(E_{T})}^{1}(\\ell^1({S_{T}}), \\ell^{\\infty}(S_{T})) $ are equal, where $E$ and $E_{T}$ are sets of idempotent elements in $S$ and $S _{T}$, respectively. Which in particular means that $\\ell^1(S)$ is weak $\\ell^1(E)$-module amenable if and only if $\\ell^1(S_T)$ is weak $\\ell^1(E_T)$-module amenable. Finally, by giving an example, we show that the condition of bijectivity for $T$, is necessary.","PeriodicalId":44941,"journal":{"name":"Boletim Sociedade Paranaense de Matematica","volume":null,"pages":null},"PeriodicalIF":0.4000,"publicationDate":"2022-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Boletim Sociedade Paranaense de Matematica","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5269/bspm.51414","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
Let $S$ be a discrete semigroup and $T$ be a left multiplier operator on $S$. A new product on $S$ defined by $T$ creates a new induced semigroup $S _{T} $. In this paper, we show that if $T$ is bijective, then the first module cohomology groups $ \HH_{\ell^1(E)}^{1}(\ell^1(S), \ell^{\infty}(S))$ and $ \HH_{\ell^1(E_{T})}^{1}(\ell^1({S_{T}}), \ell^{\infty}(S_{T})) $ are equal, where $E$ and $E_{T}$ are sets of idempotent elements in $S$ and $S _{T}$, respectively. Which in particular means that $\ell^1(S)$ is weak $\ell^1(E)$-module amenable if and only if $\ell^1(S_T)$ is weak $\ell^1(E_T)$-module amenable. Finally, by giving an example, we show that the condition of bijectivity for $T$, is necessary.