Séminaire CAESAR
de combinatoire additive




Séance du 16 mai 2013
(11 heures, UPMC Jussieu, couloir 15-25, salle 101):

Maria AXENOVICH
(Université de Karlruhe, Allemagne)

A regularity lemma and twins in words


For a word S, let f(S) be the largest integer m such that there are two disjoint identical (scattered) subwords of length m. Let f(n; G) = min{f(S) : S is of length n; over alphabet G}. We show that 2f(n; {0; 1}) = n- o(n) using the regularity lemma for words. In other words, any binary word of length n can be split into two identical subwords (referred to as twins) and, perhaps, a remaining subword of length o(n). We prove a similar result for k identical subwords of a word over an alphabet with at most k letters. Joint work with Y. Person and S. Puzynina.



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