English

Wold decomposition for isometries with equal range

Functional Analysis 2024-04-11 v2 Complex Variables Operator Algebras

Abstract

Let n2n \geq 2, and let V=(V1,,Vn)V=(V_1,\dots, V_n) be an nn-tuple of isometries acting on a Hilbert space H\mathcal{H}. We say that VV is an nn-tuple of isometries with equal range if VimiVjmjH=VjmjVimiHV_i^{m_i}V_j^{m_j}\mathcal{H} = V_j^{m_j} V_i^{m_i}\mathcal{H} and VimiVjmjH=VjmjVimiHV_i^{*m_i}V_j^{m_j} \mathcal{H} = V_j^{m_j} V_i^{*m_i}\mathcal{H} for mi,mjZ+m_i,m_j \in \mathbb{Z}_+, where 1i<jn1 \leq i<j \leq n. We prove that each nn-tuple of isometries with equal range admits a unique Wold decomposition. We obtain analytic models of the above class, and as a consequence, we show that the wandering data are complete unitary invariants for nn-tuples of isometries with equal range. Our results unify all prior findings on the decomposition for tuples of isometries in the existing literature.

Cite

@article{arxiv.2309.04445,
  title  = {Wold decomposition for isometries with equal range},
  author = {Satyabrata Majee and Amit Maji},
  journal= {arXiv preprint arXiv:2309.04445},
  year   = {2024}
}

Comments

33 pages. Sections 6 and 7 added in the revised version

R2 v1 2026-06-28T12:16:28.571Z