We define the notions of strong and strict recurrency for actions countable ordered groups on σ-finite non atomic measure spaces with quasi-invariant measures. show that is equivalent to existence weakly wandering sets positive measure. also certain p.m.p ergodic system not strictly recurrent, which shows are equivalent.

the purpose of this paper is to introduce the concept of pairwise f-closedness in bitopological spaces. this space contains both of pairwise strongcompactness and pairwise s-closedness and contained in pairwise quasi h-closedness. the characteristics and relationships concerning this new class ofspaces with other corresponding types are established. moreover, several ofits basic and important p...

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We examine the collective behaviour of coupled Duffing Hamiltonian systems (HS) and show the existence of measure synchronization (MS) in the quasi-periodic (QP) and -chaotic states. We show that the dynamics of coupled Duffing Hamiltonians exhibit a transition to coherent invariant measure, their orbits sharing the same phase space as the coupling strength is increased. Transitions from QP mea...

We discuss a close link between two seemingly different topics studied in the cellular automata literature: additive conservation laws and invariant probability measures. We provide an elementary proof of a simple correspondence between invariant full-support Bernoulli measures and interaction-free conserved quantities in the case of onedimensional surjective cellular automata. We also discuss ...

A finitely generated group $\Gamma$ is called strongly scale-invariant if there exists an injective endomorphism $\varphi: \Gamma \to \Gamma$ with the image $\varphi(\Gamma)$ of finite index in and subgroup $\bigcap\_{n>0}\varphi^n(\Gamma)$ finite. The only known examples such groups are virtually nilpotent, or equivalently, all have polynomial growth. question by Nekrashevych Pete asks whether...