English

The Multivariable moment problems and recursive relations

Functional Analysis 2016-10-13 v1

Abstract

Let β{βi}iZ+d\beta \equiv \{ \beta_\mathbf{i} \}_{\mathbf{i} \in \mathbb{Z}_+^d} be a dd-dimensional multisequence. Curto and Fialkow, have shown that if the infinite moment matrix M(β)M(\beta) is finite-rank positive semidefinite, then β\beta has a unique representing measure, which is rankM(β)rank M(\beta)-atomic. Further, let β(2n){βi}iZ+d,i2n\beta^{(2n)} \equiv \{ \beta_\mathbf{i} \}_{\mathbf{i} \in \mathbb{Z}_+^d, \mid \mathbf{i} \mid \leq 2n} be a given truncated multisequence, with associated moment matrix M(n)M(n) and rankM(n)=rrank M(n)=r, then β(2n)\beta^{(2n)} has an rr-atomic representing measure μ\mu supported in the semi-algebraic set K={(t1,,td)Rd:qj(t1,,td)0,1jm}K=\{ (t_1, \ldots, t_d) \in \mathbb{R}^d : q_j(t_1, \ldots, t_d) \geq 0, 1\leq j\leq m \}, where qjR[t1,,td]q_j \in \mathbb{R}[t_1, \ldots, t_d], if M(n)M(n) admits a positive rank-preserving extension M(n+1)M(n+1) and the localizing matrices Mqj(n+[degqj+12])M_{q_j}(n +[\frac{\deg q_j +1}{2}]) are positive semidefinite; moreover, μ\mu has precisely rankM(n)rankMqj(n+[degqj+12])rank M(n) - rank M_{q_j}(n +[\frac{\deg q_j +1}{2}]) atoms in Z(qj){tRd:qj(t)=0}\mathcal{Z}(q_j) \equiv \{ t\in \mathbb{R}^d: q_j(t)=0 \}. In this paper, we show that every truncated moment sequence β(2n)\beta^{(2n)} is a subsequence of an infinite recursively generated multisequence, we investigate such sequences to give an alternative proof of Curto-Fialkow's results and also to obtain a new interesting results.

Keywords

Cite

@article{arxiv.1610.03547,
  title  = {The Multivariable moment problems and recursive relations},
  author = {Kaissar Idrissi and El Hassan Zerouali},
  journal= {arXiv preprint arXiv:1610.03547},
  year   = {2016}
}

Comments

13 pages

R2 v1 2026-06-22T16:18:16.065Z