2014/02/27 by Assani, Idris, Duncan, David, Moore, Ryo · 1 citation
#37A05 #Dynamical Systems (math.DS) #FOS: Mathematics
paper · doi:10.48550/arxiv.1402.7094
In this paper, we extend Bourgain's double recurrence result to the Wiener-Wintner averages. Let (X, F, μ, T) be a standard ergodic system. We will show that for any f1, f2 ∈ L^∞(X), the double recurrence Wiener-Wintner average (1)/(N) ∑n=1N f1(Tanx)f2(Tbnx) e2πi n t converges off a single null set of X independent of t as N → ∞. Furthermore, we will show a uniform Wiener-Wintner double recurrence result: If either f1 or f2 belongs to the orthogonal complement of the Conze-Lesigne factor, then there exists a set of full measure such that the supremum on t of the absolute value of the averages above converges to 0.