Session 16. Ergodic Theory and Dynamical Systems

Correlation with strictly ergodic sequences

Tomasz Downarowicz, IMPAN and Wroclaw Univeristy of Technology, Poland
The talk is based on the joint work with Jacek Serafin
A symbolic sequence is called strictly ergodic if so is its shift orbit closure. Two symbolic sequences \(x=(x_n), y=(y_n)\) (over an alphabet consisting of complex numbers) are uncorrelated if the averages \(\frac 1n\sum_{i=1}^n x_n\overline{y_n}\) tend to zero. We are interested in determining which sequences are correlated to at least one strictly ergodic sequence. The family includes all sequences that are generic for ergodic measures (this follows easily from a theorem of Benjy Weiss [1, Theorem 4,4], but not only such. In fact, we believe that the sequences that do not have that property, is quite exceptional. The motivation for this study is the question whether the Möbius function is among the exceptional sequences, posed (most likely) by M. Boshernitzan.
References
  1. B. Weiss, Single Orbit Dynamics , CBMS Regional Conference Series in Mathematics, 95., American Mathematical Society, Providence, RI, 2000.
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