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Related papers: Critical exponents of infinite balanced words

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In the study of infinite words, various notions of balancedness provide quantitative measures for how regularly letters or factors occur, and they find applications in several areas of mathematics and theoretical computer science. In this…

Combinatorics · Mathematics 2026-02-04 Bastiàn Espinoza , Pierre Popoli , Manon Stipulanti

We consider the following problem. Let us fix a finite alphabet A; for any given d-uple of letter frequencies, how to construct an infinite word u over the alphabet A satisfying the following conditions: u has linear complexity function, u…

Formal Languages and Automata Theory · Computer Science 2011-08-19 Valérie Berthé , Sébastien Labbé

We determine the minimum possible critical exponent for all palindromes over finite alphabets.

Formal Languages and Automata Theory · Computer Science 2016-12-21 Jeffrey Shallit

We study how much injective morphisms can increase the repetitiveness of a given word. This question has a few possible variations depending on the meaning of ``repetitiveness''. We concentrate on fractional exponents of finite words and…

Combinatorics · Mathematics 2025-06-06 Eva Foster , Aleksi Saarela , Aleksi Vanhatalo

We study the properties of the ternary infinite word p = 012102101021012101021012 ... , that is, the fixed point of the map h:0->01, 1->21, 2->0. We determine its factor complexity, critical exponent, and prove that it is 2-balanced. We…

Discrete Mathematics · Computer Science 2022-06-07 James Currie , Pascal Ochem , Narad Rampersad , Jeffrey Shallit

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

The critical exponent of an infinite word $\bf x$ is the supremum, over all finite nonempty factors $f$, of the exponent of $f$. In this note we show that for all integers $k\geq 2,$ there is a binary infinite $k$-automatic sequence with…

Combinatorics · Mathematics 2026-02-25 J. -P. Allouche , N. Rampersad , J. Shallit

We present a method for the enumeration of restricted words over a finite alphabet. Restrictions are described through the inclusion or exclusion of suitable building blocks used to construct the words by concatenation. Our approach, which…

Combinatorics · Mathematics 2016-01-05 Daniel Birmajer , Juan B. Gil , Michael D. Weiner

Using a new approach based on automatic sequences, logic, and a decision procedure, we reprove some old theorems about circularly squarefree words and unbordered conjugates in a new and simpler way. Furthermore, we prove three new results…

Formal Languages and Automata Theory · Computer Science 2019-04-18 Trevor Clokie , Daniel Gabric , Jeffrey Shallit

The complement $\overline{x}$ of a binary word $x$ is obtained by changing each $0$ in $x$ to $1$ and vice versa. We study infinite binary words $\bf w$ that avoid sufficiently large complementary factors; that is, if $x$ is a factor of…

We characterize the squares occurring in infinite overlap-free binary words and construct various alpha power-free binary words containing infinitely many overlaps.

Combinatorics · Mathematics 2007-05-23 James Currie , Narad Rampersad , Jeffrey Shallit

We exhibit a recurrence on the number of discrete line segments joining two integer points in the plane using an encoding of such segments as balanced words of given length and height over the two-letter alphabet $\{0,1\}$. We give…

Combinatorics · Mathematics 2010-07-30 Nicolas Bedaride , Eric Domenjoud , Damien Jamet , Jean-Luc Remy

We develop a new tool, namely polynomial and linear algebraic methods, for studying systems of word equations. We illustrate its usefulness by giving essentially simpler proofs of several hard problems. At the same time we prove extensions…

Combinatorics · Mathematics 2015-02-10 Aleksi Saarela

In this paper, we characterize by lexicographic order all finite Sturmian and episturmian words, i.e., all (finite) factors of such infinite words. Consequently, we obtain a characterization of infinite episturmian words in a "wide sense"…

Combinatorics · Mathematics 2010-03-16 Amy Glen , Jacques Justin , Giuseppe Pirillo

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

This survey paper discusses five equivalent ways of defining a ``critical point at infinity'' for a complex polynomial of two variables.

alg-geom · Mathematics 2008-02-03 Alan H. Durfee

We construct an infinite binary word with critical exponent 3 that avoids abelian 4-powers. Our method gives an algorithm to determine if certain types of morphic sequences avoid additive powers. We also show that there are…

Combinatorics · Mathematics 2021-11-16 James Currie , Lucas Mol , Narad Rampersad , Jeffrey Shallit

Recently, a new characterization of Lyndon words that are also perfectly clustering was proposed by Lapointe and Reutenauer (2024). A word over a ternary alphabet {a,b,c} is called perfectly clustering Lyndon if and only if it is the…

Combinatorics · Mathematics 2024-06-25 Mélodie Lapointe , Nathan Plourde-Hébert

Any finite word $w$ of length $n$ contains at most $n+1$ distinct palindromic factors. If the bound $n+1$ is reached, the word $w$ is called rich. The number of rich words of length $n$ over an alphabet of cardinality $q$ is denoted…

Combinatorics · Mathematics 2019-03-26 Josef Rukavicka

Generalizing the results of Thue (for n = 2) and of Klepinin and Sukhanov (for n = 3), we prove that for all n greater than or equal to 2, the critical exponent of the Arshon word of order $n$ is given by (3n-2)/(2n-2), and this exponent is…

Combinatorics · Mathematics 2008-04-03 Dalia Krieger