PreprintCC BY 4.0arXiv
Wold-type decompositions for norm-increasing m-concave weighted shifts on directed trees
Abstract
In this article, we show that every norm-increasing $3$-concave weighted shift on a directed tree admits Wold-type decomposition. We then classify the $4$-isometries within a class of weighted shifts on a rootless directed tree introduced by S. Chavan and S. Trivedi, and use this classification to construct analytic norm-increasing strict $4$-isometries without the wandering subspace property. This answers a question of S. Shimorin in the negative for every m∈ ℤgeqslant 4.
Related
BibTeX
@misc{kujur2026woldtype,
title = {{Wold-type decompositions for norm-increasing $m$-concave weighted shifts on directed trees}},
author = {Ashish Kujur},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14662},
eprint = {2609.14662},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14662},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Wold-type decompositions for norm-increasing m-concave weighted shifts on directed trees
AU - Ashish Kujur
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2609.14662
UR - https://arxiv.org/abs/2609.14662
AB - In this article, we show that every norm-increasing $3$-concave weighted shift on a directed tree admits Wold-type decomposition. We then classify the $4$-isometries within a class of weighted shifts on a rootless directed tree introduced by S. Chavan and S. Trivedi, and use this classification to construct analytic norm-increasing strict $4$-isometries without the wandering subspace property. This answers a question of S. Shimorin in the negative for every m∈ ℤ_geqslant 4.
ER -