{ "id": "2411.00675", "version": "v1", "published": "2024-11-01T15:34:56.000Z", "updated": "2024-11-01T15:34:56.000Z", "title": "On integral $\\mathrm{Ext^2}$ between certain Weyl modules of $\\mathrm{GLn}$", "authors": [ "Maria Metzaki" ], "categories": [ "math.RT" ], "abstract": "Consider partitions of the form $\\lambda=(a,1^b)$ and $\\mu=(a+1,b-1)$,\\\\ where $a+1>b-1$. In this paper, we determine the extension groups $\\mathrm{Ext}_A^2(K_{\\lambda}F,K_{\\mu}F)$, where $F$ is a free $\\mathbb{Z}-$module of finite rank $n$, $K_{\\lambda}F$ and $K_{\\mu}F$ are the Weyl modules of the general linear group $GL_n(\\mathbb{Z})$ corresponding to $\\lambda$ and $\\mu$, respectively, $A=S_\\mathbb{Z}(n,r)$ is the integral Schur algebra and $r=a+b$.", "revisions": [ { "version": "v1", "updated": "2024-11-01T15:34:56.000Z" } ], "analyses": { "subjects": [ "20G05" ], "keywords": [ "weyl modules", "integral schur algebra", "general linear group", "extension groups", "finite rank" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }