Acoustic waves around an infinite configuration of identical circular scatterers are considered. Each scatterer is close to a node of a regular lattice: the geometrical configuration is almost periodic. Analytical estimates for the average field in such a random medium are obtained. Introduction Consider waves in a two-dimensional periodic structure, defined by a lattice Λ: each cell in the lat...

Seven cloned small circular DNA molecules from CHO cells were sequenced and examined for the presence of homologies to each other and to a number of other functional sequences present in transposable elements, retroviruses, mammalian repeat sequences, and introns. The sequences of the CHO cell circular DNA molecules did not reveal common structural features that could explain their presence in ...

a non-abelian finite group is called sequenceable if for some positive integer , is -generated ( ) and there exist integers such that every element of is a term of the -step generalized fibonacci sequence , , , . a remarkable application of this definition may be find on the study of random covers in the cryptography. the 2-step generalized sequences for the dihedral groups studied for their pe...

In this survey we describe how the so-called Dold congruence arises in topology, and it relates to periodic point counting dynamical systems.