{ "id": "1610.00936", "version": "v1", "published": "2016-10-04T11:36:50.000Z", "updated": "2016-10-04T11:36:50.000Z", "title": "On decomposition of operators having $Γ_3$ as a spectral set", "authors": [ "Sourav Pal" ], "comment": "Submitted", "categories": [ "math.FA", "math.CV" ], "abstract": "The symmetrized polydisc of dimension three is the set \\[ \\Gamma_3 =\\{ (z_1+z_2+z_3, z_1z_2+z_2z_3+z_3z_1, z_1z_2z_3)\\,:\\, |z_i|\\leq 1 \\,,\\, i=1,2,3 \\} \\subseteq \\mathbb C^3\\,. \\] A triple of commuting operators for which $\\Gamma_3$ is a spectral set is called a $\\Gamma_3$-contraction. We show that every $\\Gamma_3$-contraction admits a decomposition into a $\\Gamma_3$-unitary and a completely non-unitary $\\Gamma_3$-contraction. This decomposition parallels the canonical decomposition of a contraction into a unitary and a completely non-unitary contraction. We also find new characterizations for the set $\\Gamma_3$ and $\\Gamma_3$-contractions.", "revisions": [ { "version": "v1", "updated": "2016-10-04T11:36:50.000Z" } ], "analyses": { "keywords": [ "spectral set", "contraction admits", "decomposition parallels", "non-unitary contraction" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }