منابع مشابه
Periodic Subwords in 2-piece Words
We find families of words W where W is a product of k pieces for k=2. For k=3,4,6, W arises in a small cancellation group with single defining relation W=1. We assume W involves generators but not their inverses and does not have a periodic cyclic permutation (like XY...XYX for nonempty base word XY). We prove W or W written backwards equals ABCD where ABC, CDA are periodic words with base word...
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We examine words w satisfying the following property: if x is a subword of w and |x| is at least k for some fixed k, then the reversal of x is not a subword of w.
متن کاملIntersecting periodic words
Let a = a[1..2v] be a word which is a square and for which a[1..2u] is also a square and a[k + 1..min(k + 2w, 2v)] has period w where u < w < v < 2u and 0 ≤ k ≤ v − u. We show that under certain extra conditions on k and w the word has period gcd(u, v, w) and describe the word’s structure when these extra conditions do not hold. c © 2006 Elsevier B.V. All rights reserved.
متن کاملRich and Periodic-Like Words
In this paper we investigate the periodic structure of rich words (i.e., words having the highest possible number of palindromic factors), giving new results relating them with periodic-like words. In particular, some new characterizations of rich words and rich palindromes are given. We also prove that a periodic-like word is rich if and only if the square of its fractional root is also rich.
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We consider several open problems of Karhum aki, Mignosi, and Plandowski, cf. [KMP], concerning the expressibility of languages and relations as solutions of word equations. We show rst that the (scattered) subword relation is not expressible. Then, we consider the set of k-power free nite words and solve it negativelly for all nontrivial integer values of k. Finally, we consider the Fibonacci...
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ژورنال
عنوان ژورنال: Pacific Journal of Mathematics
سال: 2001
ISSN: 0030-8730
DOI: 10.2140/pjm.2001.199.493