{ "id": "0807.3580", "version": "v2", "published": "2008-07-23T00:08:50.000Z", "updated": "2009-12-17T04:34:14.000Z", "title": "Zero patterns and unitary similarity", "authors": [ "Jinpeng An", "Dragomir Z. Djokovic" ], "comment": "39 pages", "journal": "Journal of Algebra 324 (2010) 51-80", "categories": [ "math.RT" ], "abstract": "A subspace of the space, L(n), of traceless complex $n\\times n$ matrices can be specified by requiring that the entries at some positions $(i,j)$ be zero. The set, $I$, of these positions is a (zero) pattern and the corresponding subspace of L(n) is denoted by $L_I(n)$. A pattern $I$ is universal if every matrix in L(n) is unitarily similar to some matrix in $L_I(n)$. The problem of describing the universal patterns is raised, solved in full for $n\\le3$, and partial results obtained for $n=4$. Two infinite families of universal patterns are constructed. They give two analogues of Schur's triangularization theorem.", "revisions": [ { "version": "v2", "updated": "2009-12-17T04:34:14.000Z" } ], "analyses": { "subjects": [ "15A21", "14L35" ], "keywords": [ "unitary similarity", "zero patterns", "universal patterns", "schurs triangularization theorem", "partial results" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 39, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0807.3580A" } } }