English

Decomposition of the tensor product of two Hilbert modules

Functional Analysis 2019-06-11 v1

Abstract

Given a pair of positive real numbers α,β\alpha, \beta and a sesqui-analytic function KK on a bounded domain ΩCm\Omega \subset \mathbb C^m, in this paper, we investigate the properties of the sesqui-analytic function K(α,β):=Kα+β(iˉjlogK)i,j=1m,\mathbb K^{(\alpha, \beta)}:= K^{\alpha+\beta}\big(\partial_i\bar{\partial}_j\log K\big )_{i,j=1}^ m, taking values in m×mm\times m matrices. One of the key findings is that K(α,β)\mathbb K^{(\alpha, \beta)} is non-negative definite whenever KαK^\alpha and KβK^\beta are non-negative definite. In this case, a realization of the Hilbert module determined by the kernel K(α,β)\mathbb K^{(\alpha,\beta)} is obtained. Let Mi\mathcal M_i, i=1,2,i=1,2, be two Hilbert modules over the polynomial ring C[z1,,zm]\mathbb C[z_1, \ldots, z_m]. Then C[z1,,z2m]\mathbb C[z_1, \ldots, z_{2m}] acts naturally on the tensor product M1M2\mathcal M_1\otimes \mathcal M_2. The restriction of this action to the polynomial ring C[z1,,zm]\mathbb C[z_1, \ldots, z_m] obtained using the restriction map ppΔp \mapsto p_{|\Delta} leads to a natural decomposition of the tensor product M1M2\mathcal M_1\otimes \mathcal M_2, which is investigated. Two of the initial pieces in this decomposition are identified.

Keywords

Cite

@article{arxiv.1906.03687,
  title  = {Decomposition of the tensor product of two Hilbert modules},
  author = {Soumitra Ghara and Gadadhar Misra},
  journal= {arXiv preprint arXiv:1906.03687},
  year   = {2019}
}