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We study the cycle structure of words in several random permutations. We assume that the permutations are independent and that their distribution is conjugation invariant, with a good control on their short cycles. If, after successive…

Combinatorics · Mathematics 2023-10-24 Mohamed Slim Kammoun , Mylène Maïda

We investigate the problem of the maximum number of cubic subwords (of the form $www$) in a given word. We also consider square subwords (of the form $ww$). The problem of the maximum number of squares in a word is not well understood.…

Formal Languages and Automata Theory · Computer Science 2015-05-14 Marcin Kubica , Jakub Radoszewski , Wojciech Rytter , Tomasz Walen

A circular word, or a necklace, is an equivalence class under conjugation of a word. A fundamental question concerning regularities in standard words is bounding the number of distinct squares in a word of length $n$. The famous conjecture…

Formal Languages and Automata Theory · Computer Science 2017-08-03 Mika Amit , Paweł Gawrychowski

We introduced the notation of a set of prohibitions and give definitions of a complete set and a crucial word with respect to a given set of prohibitions. We consider 3 particular sets which appear in different areas of mathematics and for…

Combinatorics · Mathematics 2007-05-23 A. Evdokimov , S. Kitaev

We implement a decision procedure for answering questions about a class of infinite words that might be called (for lack of a better name) "Fibonacci-automatic". This class includes, for example, the famous Fibonacci word f = 01001010...,…

Formal Languages and Automata Theory · Computer Science 2014-07-29 Chen Fei Du , Hamoon Mousavi , Luke Schaeffer , Jeffrey Shallit

The avoidability, or unavoidability of patterns in words over finite alphabets has been studied extensively. A word (pattern) over a finite set is said to be unavoidable if, for all but finitely many words, there exists a morphism mapping…

Formal Languages and Automata Theory · Computer Science 2019-07-16 Paul Sauer

We study the structure of the language of binary cube-free words. Namely, we are interested in the cube-free words that cannot be infinitely extended preserving cube-freeness. We show the existence of such words with arbitrarily long finite…

Formal Languages and Automata Theory · Computer Science 2011-08-19 Elena A. Petrova , Arseny M. Shur

Cross-bifix-free sets are sets of words such that no prefix of any word is a suffix of any other word. In this paper, we introduce a general constructive method for the sets of cross-bifix-free binary words of fixed length. It enables us to…

Formal Languages and Automata Theory · Computer Science 2011-12-15 Stefano Bilotta , Elisa Pergola , Renzo Pinzani

A word w is rich if it has |w|+1 many distinct palindromic factors, including the empty word. A word is square-free if it does not have a factor uu, where u is a non-empty word. Pelantov\'a and Starosta (Discrete Math. 313 (2013)) proved…

Combinatorics · Mathematics 2016-03-04 Jetro Vesti

A word is said to be \emph{bordered} if it contains a non-empty proper prefix that is also a suffix. We can naturally extend this definition to pairs of non-empty words. A pair of words $(u,v)$ is said to be \emph{mutually bordered} if…

Discrete Mathematics · Computer Science 2022-06-30 Daniel Gabric

The (bitwise) complement $\overline{x}$ of a binary word $x$ is obtained by changing each $0$ in $x$ to $1$ and vice versa. An $\textit{antisquare}$ is a nonempty word of the form $x\, \overline{x}$. In this paper, we study infinite binary…

Combinatorics · Mathematics 2024-02-14 Aseem Baranwal , James Currie , Lucas Mol , Pascal Ochem , Narad Rampersad , Jeffrey Shallit

We present an algorithm that takes an unannotated corpus as its input, and returns a ranked list of probable morphologically related pairs as its output. The algorithm tries to discover morphologically related pairs by looking for pairs…

Computation and Language · Computer Science 2007-05-23 Marco Baroni , Johannes Matiasek , Harald Trost

Carpi constructed an infinite word over a 4-letter alphabet that avoids squares in all subsequences indexed by arithmetic progressions of odd difference. We show a connection between Carpi's construction and the paperfolding words. We…

Combinatorics · Mathematics 2007-05-23 Jui-Yi Kao , Narad Rampersad , Jeffrey Shallit , Manuel Silva

The relationship between the length of a word and the maximum length of its unbordered factors is investigated in this paper. Consider a finite word w of length n. We call a word bordered, if it has a proper prefix which is also a suffix of…

Discrete Mathematics · Computer Science 2007-05-23 Tero Harju , Dirk Nowotka

A correlation is a binary vector that encodes all possible positions of overlaps of two words, where an overlap for an ordered pair of words (u,v) occurs if a suffix of word u matches a prefix of word v. As multiple pairs can have the same…

Discrete Mathematics · Computer Science 2025-06-03 Eric Rivals , Pengfei Wang

A permutation is said to be a square if it can be obtained by shuffling two order-isomorphic patterns. The definition is intended to be the natural counterpart to the ordinary shuffle of words and languages. In this paper, we tackle the…

Data Structures and Algorithms · Computer Science 2016-03-04 Samuele Giraudo , Stéphane Vialette

We introduce the notion of unavoidable (complete) sets of word patterns, which is a refinement for that of words, and study certain numerical characteristics for unavoidable sets of patterns. In some cases we employ the graph of pattern…

Combinatorics · Mathematics 2007-05-23 Alexander Burstein , Sergey Kitaev

We consider questions related to the structure of infinite words (over an integer alphabet) with bounded additive complexity, i.e., words with the property that the number of distinct sums exhibited by factors of the same length is bounded…

Combinatorics · Mathematics 2012-09-24 Graham Banero

We consider avoiding squares and overlaps over the natural numbers, using a greedy algorithm that chooses the least possible integer at each step; the word generated is lexicographically least among all such infinite words. In the case of…

Combinatorics · Mathematics 2009-04-12 Mathieu Guay-Paquet , Jeffrey Shallit

A binary shuffle square is a binary word of even length that can be partitioned into two disjoint, identical subwords. Huang, Nam, Thaper, and the first author conjectured that as $n\rightarrow \infty$, asymptotically half of all binary…

Combinatorics · Mathematics 2025-12-16 Xiaoyu He , Logan Post