English

Pointwise entangled ergodic theorems for Dunford-Schwartz operators

Functional Analysis 2018-07-18 v1 Dynamical Systems

Abstract

We investigate pointwise convergence of entangled ergodic averages of Dunford-Schwartz operators T0,T1,,TmT_0,T_1,\ldots, T_m on a Borel probability space. These averages take the form 1Nk1n1,,nkNTmnα(m)Am1Tm1nα(m1)A2T2nα(2)A1T1nα(1)f, \frac{1}{N^k}\sum_{1\leq n_1,\ldots, n_k\leq N} T_m^{n_{\alpha(m)}}A_{m-1}T^{n_{\alpha(m-1)}}_{m-1}\ldots A_2T_2^{n_{\alpha(2)}}A_1T_1^{n_{\alpha(1)}} f, where fLp(X,μ)f\in L^p(X,\mu) for some 1p<1\leq p<\infty, and α:{1,,m}{1,,k}\alpha:\left\{1,\ldots,m\right\}\to\left\{1,\ldots,k\right\} encodes the entanglement. We prove that under some joint boundedness and twisted compactness conditions on the pairs (Ai,Ti)(A_i,T_i), almost everywhere convergence holds for all fLpf\in L^p. We also present an extension to polynomial powers in the case p=2p=2, in addition to a continuous version concerning Dunford-Schwartz C0C_0-semigroups.

Keywords

Cite

@article{arxiv.1705.07693,
  title  = {Pointwise entangled ergodic theorems for Dunford-Schwartz operators},
  author = {Dávid Kunszenti-Kovács},
  journal= {arXiv preprint arXiv:1705.07693},
  year   = {2018}
}

Comments

16 pages

R2 v1 2026-06-22T19:54:35.386Z