English

Contractive Hilbert modules on quotient domains

Functional Analysis 2024-09-18 v1

Abstract

Let the complex reflection group G(m,p,n)G(m,p,n) act on the unit polydisc Dn\mathbb D^n in Cn.\mathbb C^n. A Θn\boldsymbol\Theta_n-contraction is a commuting tuple of operators on a Hilbert space having Θn:={θ(z)=(θ1(z),,θn(z)):zDn}\overline{\boldsymbol\Theta}_n:=\{\boldsymbol\theta(z)=(\theta_1(z),\ldots,\theta_n(z)):z\in\overline{\mathbb D}^n\} as a spectral set, where {θi}i=1n\{\theta_i\}_{i=1}^n is a homogeneous system of parameters associated to G(m,p,n).G(m,p,n). A plethora of examples of Θn\boldsymbol\Theta_n-contractions is exhibited. Under a mild hypothesis, it is shown that these Θn\boldsymbol\Theta_n-contractions are mutually unitarily inequivalent. These inequivalence results are obtained concretely for the weighted Bergman modules under the action of the permutation groups and the dihedral groups. The division problem is shown to have negative answers for the Hardy module and the Bergman module on the bidisc. A Beurling-Lax-Halmos type representation for the invariant subspaces of Θn\boldsymbol\Theta_n-isometries is obtained.

Keywords

Cite

@article{arxiv.2409.11101,
  title  = {Contractive Hilbert modules on quotient domains},
  author = {Shibananda Biswas and Gargi Ghosh and E. K. Narayanan and Subrata Shyam Roy},
  journal= {arXiv preprint arXiv:2409.11101},
  year   = {2024}
}

Comments

23 pages. arXiv admin note: text overlap with arXiv:1301.2837

R2 v1 2026-06-28T18:47:42.153Z