Table of Contents
Fetching ...

Stable division and essential normality: the non-homogeneous and quasi homogeneous cases

Shibananda Biswas, Orr Shalit

TL;DR

This work advances the Arvesonouglas program by showing that closures of ideals with stable/approximate stable division in the Hilbert spaces al H_d^{(t)} are p-ssentially normal for all p>d (for t>-3). It proves that quasi homogeneous ideals in two variables have the stable division property, and combines these results to yield a new proof that closures of quasi homogeneous ideals in C[x,y] are p-ssentially normal for p>2 on al H_2^{(t)} (t  -2). The approach centers on expressing ideals as sums of principal (or stable) submodules via stable division, leveraging principal-ideal essential normality results and Beurling-type reductions to extend to general ideals. This stable-division framework provides a versatile method for establishing essential normality beyond homogeneous cases and offers new lines of evidence toward the two-variable Arvesonouglas conjecture with potential extensions to broader settings.

Abstract

Let $\mathcal{H}_d^{(t)}$ ($t \geq -d$, $t>-3$) be the reproducing kernel Hilbert space on the unit ball $\mathbb{B}_d$ with kernel \[ k(z,w) = \frac{1}{(1-\langle z, w \rangle)^{d+t+1}} . \] We prove that if an ideal $I \triangleleft \mathbb{C}[z_1, \ldots, z_d]$ (not necessarily homogeneous) has what we call the "approximate stable division property", then the closure of $I$ in $\mathcal{H}_d^{(t)}$ is $p$-essentially normal for all $p>d$. We then show that all quasi homogeneous ideals in two variables have the stable division property, and combine these two results to obtain a new proof of the fact that the closure of any quasi homogeneous ideal in $\mathbb{C}[x,y]$ is $p$-essentially normal for $p>2$.

Stable division and essential normality: the non-homogeneous and quasi homogeneous cases

TL;DR

This work advances the Arvesonouglas program by showing that closures of ideals with stable/approximate stable division in the Hilbert spaces al H_d^{(t)} are p-ssentially normal for all p>d (for t>-3). It proves that quasi homogeneous ideals in two variables have the stable division property, and combines these results to yield a new proof that closures of quasi homogeneous ideals in C[x,y] are p-ssentially normal for p>2 on al H_2^{(t)} (t  -2). The approach centers on expressing ideals as sums of principal (or stable) submodules via stable division, leveraging principal-ideal essential normality results and Beurling-type reductions to extend to general ideals. This stable-division framework provides a versatile method for establishing essential normality beyond homogeneous cases and offers new lines of evidence toward the two-variable Arvesonouglas conjecture with potential extensions to broader settings.

Abstract

Let (, ) be the reproducing kernel Hilbert space on the unit ball with kernel We prove that if an ideal (not necessarily homogeneous) has what we call the "approximate stable division property", then the closure of in is -essentially normal for all . We then show that all quasi homogeneous ideals in two variables have the stable division property, and combine these two results to obtain a new proof of the fact that the closure of any quasi homogeneous ideal in is -essentially normal for .

Paper Structure

This paper contains 9 sections, 11 theorems, 53 equations.

Key Result

Lemma 2.1

Let $M_1, \ldots, M_k$ be linear subspaces of a Hilbert space $H$. Let $M = M_1 + \ldots + M_k$ denote the algebraic sum of these spaces inside $H$, and let $\overline{M_1} \oplus \ldots \oplus \overline{M_k}$ denote the (disjoint) orthogonal sum formed by them. Consider the map given by Then the following are equivalent: In case that all the subspaces $M_i$ are closed, then (1) implies (2) wit

Theorems & Definitions (25)

  • Definition 1.1
  • Lemma 2.1
  • proof
  • Remark 2.2
  • Theorem 2.3
  • proof
  • Theorem 2.4
  • proof
  • Proposition 2.5: Fang-Xia
  • Remark 2.6
  • ...and 15 more