{"title":"双仿射布鲁哈特目封面的分类","authors":"Amanda Welch","doi":"10.37236/10745","DOIUrl":null,"url":null,"abstract":"We classify cocovers of a given element of the double affine Weyl semigroup $W_{\\mathcal{T}}$ with respect to the Bruhat order, specifically when $W_{\\mathcal{T}}$ is associated to a finite root system that is irreducible and simply laced. We do so by introducing a graphical representation of the length difference set defined by Muthiah and Orr and identifying the cocovering relations with the corners of those graphs. This new method allows us to prove that there are finitely many cocovers of each $x \\in W_{\\mathcal{T}}$. Further, we show that the Bruhat intervals in the double affine Bruhat order are finite.","PeriodicalId":11515,"journal":{"name":"Electronic Journal of Combinatorics","volume":"21 1","pages":""},"PeriodicalIF":0.7000,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Classification of Cocovers in the Double Affine Bruhat Order\",\"authors\":\"Amanda Welch\",\"doi\":\"10.37236/10745\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We classify cocovers of a given element of the double affine Weyl semigroup $W_{\\\\mathcal{T}}$ with respect to the Bruhat order, specifically when $W_{\\\\mathcal{T}}$ is associated to a finite root system that is irreducible and simply laced. We do so by introducing a graphical representation of the length difference set defined by Muthiah and Orr and identifying the cocovering relations with the corners of those graphs. This new method allows us to prove that there are finitely many cocovers of each $x \\\\in W_{\\\\mathcal{T}}$. Further, we show that the Bruhat intervals in the double affine Bruhat order are finite.\",\"PeriodicalId\":11515,\"journal\":{\"name\":\"Electronic Journal of Combinatorics\",\"volume\":\"21 1\",\"pages\":\"\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2022-10-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Electronic Journal of Combinatorics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.37236/10745\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Electronic Journal of Combinatorics","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.37236/10745","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Classification of Cocovers in the Double Affine Bruhat Order
We classify cocovers of a given element of the double affine Weyl semigroup $W_{\mathcal{T}}$ with respect to the Bruhat order, specifically when $W_{\mathcal{T}}$ is associated to a finite root system that is irreducible and simply laced. We do so by introducing a graphical representation of the length difference set defined by Muthiah and Orr and identifying the cocovering relations with the corners of those graphs. This new method allows us to prove that there are finitely many cocovers of each $x \in W_{\mathcal{T}}$. Further, we show that the Bruhat intervals in the double affine Bruhat order are finite.
期刊介绍:
The Electronic Journal of Combinatorics (E-JC) is a fully-refereed electronic journal with very high standards, publishing papers of substantial content and interest in all branches of discrete mathematics, including combinatorics, graph theory, and algorithms for combinatorial problems.