{"title":"莫比乌斯群的表示和考文-道格拉斯类同质算子对","authors":"Jyotirmay Das, Somnath Hazra","doi":"arxiv-2408.03711","DOIUrl":null,"url":null,"abstract":"Let M\\\"ob be the biholomorphic automorphism group of the unit disc of the\ncomplex plane, $\\mathcal{H}$ be a complex separable Hilbert space and\n$\\mathcal{U}(\\mathcal{H})$ be the group of all unitary operators. Suppose\n$\\mathcal{H}$ is a reproducing kernel Hilbert space consisting of holomorphic\nfunctions over the poly-disc $\\mathbb D^n$ and contains all the polynomials. If\n$\\pi : \\mbox{M\\\"ob} \\to \\mathcal{U}(\\mathcal{H})$ is a multiplier\nrepresentation, then we prove that there exist $\\lambda_1, \\lambda_2, \\ldots,\n\\lambda_n > 0$ such that $\\pi$ is unitarily equivalent to $(\\otimes_{i=1}^{n}\nD_{\\lambda_i}^+)|_{\\mbox{M\\\"ob}}$, where each $D_{\\lambda_i}^+$ is a\nholomorphic discrete series representation of M\\\"ob. As an application, we\nprove that if $(T_1, T_2)$ is a M\\\"ob - homogeneous pair in the Cowen - Douglas\nclass of rank $1$ over the bi-disc, then each $T_i$ posses an upper triangular\nform with respect to a decomposition of the Hilbert space. In this upper\ntriangular form of each $T_i$, the diagonal operators are identified. We also\nprove that if $\\mathcal{H}$ consists of symmetric (resp. anti-symmetric)\nholomorphic functions over $\\mathbb D^2$ and contains all the symmetric (resp.\nanti-symmetric) polynomials, then there exists $\\lambda > 0$ such that $\\pi\n\\cong \\oplus_{m = 0}^\\infty D^+_{\\lambda + 4m}$ (resp. $\\pi \\cong\n\\oplus_{m=0}^\\infty D^+_{\\lambda + 4m + 2}$).","PeriodicalId":501036,"journal":{"name":"arXiv - MATH - Functional Analysis","volume":"75 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Representations of the Möbius group and pairs of homogeneous operators in the Cowen-Douglas class\",\"authors\":\"Jyotirmay Das, Somnath Hazra\",\"doi\":\"arxiv-2408.03711\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Let M\\\\\\\"ob be the biholomorphic automorphism group of the unit disc of the\\ncomplex plane, $\\\\mathcal{H}$ be a complex separable Hilbert space and\\n$\\\\mathcal{U}(\\\\mathcal{H})$ be the group of all unitary operators. Suppose\\n$\\\\mathcal{H}$ is a reproducing kernel Hilbert space consisting of holomorphic\\nfunctions over the poly-disc $\\\\mathbb D^n$ and contains all the polynomials. If\\n$\\\\pi : \\\\mbox{M\\\\\\\"ob} \\\\to \\\\mathcal{U}(\\\\mathcal{H})$ is a multiplier\\nrepresentation, then we prove that there exist $\\\\lambda_1, \\\\lambda_2, \\\\ldots,\\n\\\\lambda_n > 0$ such that $\\\\pi$ is unitarily equivalent to $(\\\\otimes_{i=1}^{n}\\nD_{\\\\lambda_i}^+)|_{\\\\mbox{M\\\\\\\"ob}}$, where each $D_{\\\\lambda_i}^+$ is a\\nholomorphic discrete series representation of M\\\\\\\"ob. As an application, we\\nprove that if $(T_1, T_2)$ is a M\\\\\\\"ob - homogeneous pair in the Cowen - Douglas\\nclass of rank $1$ over the bi-disc, then each $T_i$ posses an upper triangular\\nform with respect to a decomposition of the Hilbert space. In this upper\\ntriangular form of each $T_i$, the diagonal operators are identified. We also\\nprove that if $\\\\mathcal{H}$ consists of symmetric (resp. anti-symmetric)\\nholomorphic functions over $\\\\mathbb D^2$ and contains all the symmetric (resp.\\nanti-symmetric) polynomials, then there exists $\\\\lambda > 0$ such that $\\\\pi\\n\\\\cong \\\\oplus_{m = 0}^\\\\infty D^+_{\\\\lambda + 4m}$ (resp. $\\\\pi \\\\cong\\n\\\\oplus_{m=0}^\\\\infty D^+_{\\\\lambda + 4m + 2}$).\",\"PeriodicalId\":501036,\"journal\":{\"name\":\"arXiv - MATH - Functional Analysis\",\"volume\":\"75 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-08-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Functional Analysis\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2408.03711\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - MATH - Functional Analysis","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2408.03711","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Representations of the Möbius group and pairs of homogeneous operators in the Cowen-Douglas class
Let M\"ob be the biholomorphic automorphism group of the unit disc of the
complex plane, $\mathcal{H}$ be a complex separable Hilbert space and
$\mathcal{U}(\mathcal{H})$ be the group of all unitary operators. Suppose
$\mathcal{H}$ is a reproducing kernel Hilbert space consisting of holomorphic
functions over the poly-disc $\mathbb D^n$ and contains all the polynomials. If
$\pi : \mbox{M\"ob} \to \mathcal{U}(\mathcal{H})$ is a multiplier
representation, then we prove that there exist $\lambda_1, \lambda_2, \ldots,
\lambda_n > 0$ such that $\pi$ is unitarily equivalent to $(\otimes_{i=1}^{n}
D_{\lambda_i}^+)|_{\mbox{M\"ob}}$, where each $D_{\lambda_i}^+$ is a
holomorphic discrete series representation of M\"ob. As an application, we
prove that if $(T_1, T_2)$ is a M\"ob - homogeneous pair in the Cowen - Douglas
class of rank $1$ over the bi-disc, then each $T_i$ posses an upper triangular
form with respect to a decomposition of the Hilbert space. In this upper
triangular form of each $T_i$, the diagonal operators are identified. We also
prove that if $\mathcal{H}$ consists of symmetric (resp. anti-symmetric)
holomorphic functions over $\mathbb D^2$ and contains all the symmetric (resp.
anti-symmetric) polynomials, then there exists $\lambda > 0$ such that $\pi
\cong \oplus_{m = 0}^\infty D^+_{\lambda + 4m}$ (resp. $\pi \cong
\oplus_{m=0}^\infty D^+_{\lambda + 4m + 2}$).