A famous theorem of Szemer'edi asserts that any subset of integers with posi- tive upper density contains arbitrarily arithmetic progressions. Let Fq be a finite field with q elements and Fq((X^-1)) be the power ...
supported by National Natural Science Foundation of China (Grant Nos.10631040,10901066)
Let T : X → X be a transformation. For any x C [0, 1) and r 〉 O, the recurrence time Tr(x) of x under T in its r-neighborhood is defined as Tr(X) = inf{k ≥ 1: d(Tk(x),x) 〈 r}.For 0 ≤ α ≤ β ∞ co, le...