English

Almost everywhere convergence of entangled ergodic averages

Dynamical Systems 2016-10-06 v2 Functional Analysis

Abstract

We study pointwise convergence of entangled averages of 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 fL2(X,μ)f\in L^2(X,\mu), α:{1,,m}{1,,k}\alpha:\left\{1,\ldots,m\right\}\to\left\{1,\ldots,k\right\}, and the TiT_i are ergodic measure preserving transformations on the standard probability space (X,μ)(X,\mu). We show that under some joint boundedness and twisted compactness conditions on the pairs (Ai,Ti)(A_i,T_i), almost everywhere convergence holds for all fL2f\in L^2. We also present results for the general LpL^p case (1p<1\leq p<\infty) and for polynomial powers, in addition to continuous versions concerning ergodic flows.

Keywords

Cite

@article{arxiv.1511.01528,
  title  = {Almost everywhere convergence of entangled ergodic averages},
  author = {Dávid Kunszenti-Kovács},
  journal= {arXiv preprint arXiv:1511.01528},
  year   = {2016}
}

Comments

16 pages, to appear in Integral Equations and Operator Theory