منابع مشابه
Sequences close to periodic
The paper is a survey of notions and results related to classical and new generalizations of the notion of a periodic sequence. The topics related to almost periodicity in combinatorics on words, symbolic dynamics, expressibility in logical theories, algorithmic computability, Kolmogorov complexity, number theory, are discussed.
متن کاملDimension 1 sequences are close to randoms
We show that a sequence has effective Hausdorff dimension 1 if and only if it is coarsely similar to a Martin-Löf random sequence. More generally, a sequence has effective dimension s if and only if it is coarsely similar to a weakly s-random sequence. Further, for any s ă t, every sequence of effective dimension s can be changed on density at most H ́1ptq ́H ́1psq of its bits to produce a sequen...
متن کاملPerfect periodic correlation sequences
Sequences with the property of perfect periodic autocorrelation are used in various fields such as communication and radar systems. Various methods were introduced to construct such sequences. Most of these methods concentrated on binary or N-phase sequences. In this paper two methods to construct general phase sequences are introduced. The methods are based upon the properties of the Fourier t...
متن کاملBinary Periodic Synchronizing Sequences
In this article, we consider words over f0; 1g of length l 2. The autodistance of such a word is the lowest among the Hamming distances between the word and its images by circular permutations other than identity; the word’s reverse autodistance is the highest among these distances. For each l 2, we study the words of length l whose autodistance and reverse autodistance are close to l=2 (we cal...
متن کاملPeriodic Solutions for Functional Differential Equations with Periodic Delay Close to Zero
This paper studies the existence of periodic solutions to the delay differential equation ẋ(t) = f(x(t− μτ(t)), ) . The analysis is based on a perturbation method previously used for retarded differential equations with constant delay. By transforming the studied equation into a perturbed non-autonomous ordinary equation and using a bifurcation result and the Poincaré procedure for this last eq...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Russian Mathematical Surveys
سال: 2009
ISSN: 0036-0279,1468-4829
DOI: 10.1070/rm2009v064n05abeh004641