2024/10/15 by Ryzhikov, Valery V.
#Dynamical Systems (math.DS) #FOS: Mathematics
paper · doi:10.48550/arxiv.2410.11787
We answer the question of Frantzikinakis and Host about the convergence of ergodic (n2,n3)-averages and consider a more general case. Let sequences p(n), q(n) satisfy the property p(n+1)- p(n), q(n+1)- q(n) → +∞. Then there exist automorphisms S,T with simple singular spectrum and a set C such that the sequence ∑n=1N μ(S p(n)C∩ T q(n)C)/N diverges. We give also example of linear non-recurrence for a pair of mixing suspensions of zero entropy and with singular and Lebesgue parts in their spectra.