No Arabic abstract
Generalized polynomials are mappings obtained from the conventional polynomials by the use of operations of addition, multiplication and taking the integer part. Extending the classical theorem of H. Weyl on equidistribution of polynomials, we show that a generalized polynomial $q(n)$ has the property that the sequence $(q(n) lambda)_{n in mathbb{Z}}$ is well distributed $bmod , 1$ for all but countably many $lambda in mathbb{R}$ if and only if $limlimits_{substack{|n| rightarrow infty n otin J}} |q(n)| = infty$ for some (possibly empty) set $J$ having zero density in $mathbb{Z}$. We also prove a version of this theorem along the primes (which may be viewed as an extension of classical results of I. Vinogradov and G. Rhin). Finally, we utilize these results to obtain new examples of sets of recurrence and van der Corput sets.
Sahlqvist formulas are a syntactically specified class of modal formulas proposed by Hendrik Sahlqvist in 1975. They are important because of their first-order definability and canonicity, and hence axiomatize complete modal logics. The first-order properties definable by Sahlqvist formulas were syntactically characterized by Marcus Kracht in 1993. The present paper extends Krachts theorem to the class of `generalized Sahlqvist formulas introduced by Goranko and Vakarelov and describes an appropriate generalization of Kracht formulas.
We establish various analogs of the Kronecker-Weyl equidistribution theorem that can be considered higher-dimension
In this paper, we will give an extension of Moks theorem on the generalized Frankel conjecture under the condition of the orthogonal bisectional curvature.
Exploiting the recent work of Tao and Ziegler on the concatenation theorem on factors, we find explicit characteristic factors for multiple averages along polynomials on systems with commuting transformations, and use them to study the criteria of joint ergodicity for sequences of the form $(T^{p_{1,j}(n)}_{1}cdotldotscdot T^{p_{d,j}(n)}_{d})_{ninmathbb{Z}},$ $1leq jleq k$, where $T_{1},dots,T_{d}$ are commuting measure preserving transformations on a probability measure space and $p_{i,j}$ are integer polynomials. To be more precise, we provide a sufficient condition for such sequences to be jointly ergodic. We also give a characterization for sequences of the form $(T^{p(n)}_{i})_{ninmathbb{Z}}, 1leq ileq d$ to be jointly ergodic, answering a question due to Bergelson.
We show that the equidistribution theorem of C. Bonatti and X. Gomez-Mont for a special kind of foliations by hyperbolic surfaces does not hold in general, and seek for a weaker form valid for general foliations by hyperbolic surfaces.