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Brlek and Reutenauer conjectured that any infinite word u with language closed under reversal satisfies the equality 2D(u)=\sum_{n=0}^{\infty} T(n) in which D(u) denotes the defect of u and T(n) denotes C(n+1)-C(n)+2-P(n+1)-P(n), where C…

Combinatorics · Mathematics 2013-02-05 Lubomira Balkova , Edita Pelantova , Stepan Starosta

In this paper we investigate local to global phenomena for a new family of complexity functions of infinite words indexed by $k \in \Ni \cup \{+\infty\}$ where $\Ni$ denotes the set of positive integers. Two finite words $u$ and $v$ in…

Combinatorics · Mathematics 2013-02-18 Juhani Karhumäki , Aleksi Saarela , Luca. Q. Zamboni

We prove results about subshifts with linear (word) complexity, meaning that $\limsup \frac{p(n)}{n} < \infty$, where for every $n$, $p(n)$ is the number of $n$-letter words appearing in sequences in the subshift. Denoting this limsup by…

Dynamical Systems · Mathematics 2023-09-15 Darren Creutz , Ronnie Pavlov

In this paper we study the asymptotic behaviour of two relatively new complexity functions defined on infinite words and their relationship to periodicity. Given a factor $u$ of an infinite word $x$, we say $u$ is closed if it is a letter…

Combinatorics · Mathematics 2023-01-04 O. Parshina , M. Postic

We revisit the periodic complexity function $h_{\bf w}(n)$ introduced by Mignosi and Restivo. This function gives the average of the first $n$ local periods of a recurrent infinite word ${\bf w}$. We give a different method than that of…

Combinatorics · Mathematics 2021-12-21 Narad Rampersad

The inverse relationship between the length of a word and the frequency of its use, first identified by G.K. Zipf in 1935, is a classic empirical law that holds across a wide range of human languages. We demonstrate that length is one…

Computation and Language · Computer Science 2017-06-02 Stephan C. Meylan , Thomas L. Griffiths

Shallit and Wang studied deterministic automatic complexity of words. They showed that the automatic Hausdorff dimension $I(\mathbf t)$ of the infinite Thue word satisfies $1/3\le I(\mathbf t)\le 2/3$. We improve that result by showing that…

Formal Languages and Automata Theory · Computer Science 2020-02-03 Kayleigh Hyde , Bjørn Kjos-Hanssen

Below is a translation from my Russian paper. I added references, unavailable to me in Moscow. Similar results have been also given in [Schnorr Stumpf 75] (see also [Lynch 75]). Earlier relevant work (classical theorems like Compression,…

Computational Complexity · Computer Science 2018-12-03 Leonid A. Levin

Let $f_W(n)$ be the number of different factors of length $n$ appearing in $W$. A classical result of Morse and Hedlund, stated in 1938, asserts that an infinite word $W$ is ultimately periodic if and only if $f_W(n)\leq n$ for some $n\in…

Rings and Algebras · Mathematics 2026-05-04 M. A. Khrystik

We begin a systematic study of the relations between subword complexity of infinite words and their power avoidance. Among other things, we show that -- the Thue-Morse word has the minimum possible subword complexity over all overlap-free…

Formal Languages and Automata Theory · Computer Science 2020-07-07 Jeffrey Shallit , Arseny M. Shur

Defant and Kravitz introduced generalizations of West's stack-sorting map $s$ from permutations to finite words. This raises questions as to how such generalizations could be applied in the field of combinatorics on words. The…

Combinatorics · Mathematics 2026-04-29 John M. Campbell , Narad Rampersad

If an infinite non-periodic word is uniformly recurrent or is of bounded repetition, then the limit of its periodicity complexity is infinity. Moreover, there are uniformly recurrent words with the periodicity complexity arbitrarily high at…

Formal Languages and Automata Theory · Computer Science 2019-12-18 Štěpán Holub

We study the palindromic length of factors of infinite words fixed by morphisms of the so-called class $\mathcal{P}$ introduced by Hof, Knill and Simon. We show that it grows at most logarithmically with the length of the factor. For the…

Combinatorics · Mathematics 2018-12-05 Petr Ambrož , Ondřej Kadlec , Zuzana Masáková , Edita Pelantová

Since their introduction by Erd\H{o}s in 1950, covering systems (that is, finite collections of arithmetic progressions that cover the integers) have been extensively studied, and numerous questions and conjectures have been posed regarding…

Number Theory · Mathematics 2018-11-09 Paul Balister , Béla Bollobás , Robert Morris , Julian Sahasrabudhe , Marius Tiba

A classical result of Hensley provides a sharp lower bound for the functional $\int_\mathbb{R} t^2f$, where $f$ is a non-negative, even log-concave function. In the context of studying the minimal slabs of the unit cube, Barthe and…

Functional Analysis · Mathematics 2025-10-02 Andreas Malliaris , Francisco Marín Sola

We present an impossibility result, called a theorem about facts and words, which pertains to a general communication system. The theorem states that the number of distinct words used in a finite text is roughly greater than the number of…

Information Theory · Computer Science 2022-11-03 Łukasz Dębowski

An infinite permutation is a linear ordering of the set of natural numbers. An infinite permutation can be defined by a sequence of real numbers where only the order of elements is taken into account. In the paper we investigate a new class…

Combinatorics · Mathematics 2016-12-15 Sergey V. Avgustinovich , Anna E. Frid , Svetlana Puzynina

It was proved by Hoeffding in 1963 that a real random variable X confined to [a, b] satisfies E e^(X--E X) $\le$ e^((b--a)^2/8). We generalise this to complex random variables.

Probability · Mathematics 2016-03-03 Mikhail Isaev , Brendan D. Mckay

We show that the Word Problem in finitely generated subgroups of $\textsf{GL}_d(\mathbb{Z})$ can be solved in linear average-case complexity. This is done under the bit-complexity model, which accounts for the fact that large integers are…

Group Theory · Mathematics 2025-09-17 Frédérique Bassino , Cyril Nicaud , Pascal Weil

Given a countable set X (usually taken to be N or Z), an infinite permutation $\pi$ of X is a linear ordering $<_\pi$ of X. This paper investigates the combinatorial complexity of infinite permutations on N associated with the image of…

Combinatorics · Mathematics 2011-03-01 Steven Widmer