منابع مشابه
Abelian Repetitions in Sturmian Words
We investigate abelian repetitions in Sturmian words. We exploit a bijection between factors of Sturmian words and subintervals of the unitary segment that allows us to study the periods of abelian repetitions by using classical results of elementary Number Theory. If km denotes the maximal exponent of an abelian repetition of period m, we prove that lim sup km/m ≥ √ 5 for any Sturmian word, an...
متن کاملMaximal repetitions in strings
The cornerstone of any algorithm computing all repetitions in strings of length n in O(n) time is the fact that the number of maximal repetitions (runs) is linear. Therefore, the most important part of the analysis of the running time of such algorithms is counting the number of runs. Kolpakov and Kucherov [FOCS’99] proved it to be cn but could not provide any value for c. Recently, Rytter [STA...
متن کاملAbelian powers and repetitions in Sturmian words
Richomme, Saari and Zamboni (J. Lond. Math. Soc. 83: 79–95, 2011) proved that at every position of an infinite Sturmian word starts an abelian power of exponent k, for every positive integer k. Here, we improve on this result, studying the maximal exponent of abelian powers and abelian repetitions (an abelian repetition is the analogous of a fractional power in the abelian setting) occurring in...
متن کاملWeak Repetitions in Strings
A weak repetition in a string consists of two or more adjacent substrings which are permutations of each other. We describe a straightforward (n 2) algorithm which computes all the weak repetitions in a given string of length n deened on an arbitrary alphabet A. Using results on Fibonacci and other simple strings, we prove that this algorithm is asymptotically optimal over all known encodings o...
متن کاملTwo-Pattern Strings — Computing Repetitions & Near-Repetitions
In a recent paper we introduced infinite two-pattern strings on the alphabet {a, b} as a generalization of Sturmian strings, and we posed three questions about them: • Given a finite string x, can we in linear time O(|x|) recognize whether or not x is a prefix/substring of some infinite two-pattern string? • If recognized as two-pattern, can all the repetitions in x be computed in linear time? ...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2000
ISSN: 0304-3975
DOI: 10.1016/s0304-3975(00)00063-3