{ "id": "1910.14457", "version": "v1", "published": "2019-10-30T14:48:30.000Z", "updated": "2019-10-30T14:48:30.000Z", "title": "A criterion for discrete branching laws for Klein four symmetric pairs and its application to $E_{6(-14)}$", "authors": [ "Haian He" ], "comment": "11 pages, 1 figure. arXiv admin note: text overlap with arXiv:1908.04723", "categories": [ "math.RT" ], "abstract": "Let $G$ be a noncompact connected simple Lie group, and $(G,G^\\Gamma)$ a Klein four symmetric pair. In this paper, the author shows a necessary condition for the discrete decomposability of unitarizable simple $(\\mathfrak{g},K)$-modules for Klein for symmetric pairs. Precisely, if certain conditions hold for $(G,G^\\Gamma)$, there does not exist any unitarizable simple $(\\mathfrak{g},K)$-module that is discretely decomposable as a $(\\mathfrak{g}^\\Gamma,K^\\Gamma)$-module. As an application, for $G=\\mathrm{E}_{6(-14)}$, the author obtains a complete classification of Klein four symmetric pairs $(G,G^\\Gamma)$ with $G^\\Gamma$ noncompact, such that there exists at least one nontrivial unitarizable simple $(\\mathfrak{g},K)$-module that is discretely decomposable as a $(\\mathfrak{g}^\\Gamma,K^\\Gamma)$-module and is also discretely decomposable as a $(\\mathfrak{g}^\\sigma,K^\\sigma)$-module for some nonidentity element $\\sigma\\in\\Gamma$.", "revisions": [ { "version": "v1", "updated": "2019-10-30T14:48:30.000Z" } ], "analyses": { "subjects": [ "22E46" ], "keywords": [ "symmetric pair", "discrete branching laws", "unitarizable simple", "application", "noncompact connected simple lie group" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }