[图书][B] The logical approach to automatic sequences: Exploring combinatorics on words with Walnut

J Shallit - 2022 - books.google.com
Automatic sequences are sequences over a finite alphabet generated by a finite-state
machine. This book presents a novel viewpoint on automatic sequences, and more …

Lie complexity of words

JP Bell, J Shallit - Theoretical Computer Science, 2022 - Elsevier
Given a finite alphabet Σ and a right-infinite word w over Σ, we define the Lie complexity
function L w: N→ N, whose value at n is the number of conjugacy classes (under cyclic shift) …

[图书][B] Sequences, groups, and number theory

V Berthé, M Rigo - 2018 - Springer
This collaborative volume aims at presenting and developing recent trends at the interface
between the study of sequences, groups, and number theory, as the title may suggest. It is …

The undirected repetition threshold and undirected pattern avoidance

JD Currie, L Mol - Theoretical Computer Science, 2021 - Elsevier
For a rational number r such that 1< r≤ 2, an undirected r-power is a word of the form xyx′,
where the word x is nonempty, the word x′ is in {x, x R}, and we have| xyx′|/| xy|= r. The …

Avoidability of palindrome patterns

P Ochem, M Rosenfeld - The Electronic Journal of Combinatorics, 2021 - combinatorics.org
We characterize the formulas that are avoided by every $\alpha $-free word for some
$\alpha> 1$. We show that the avoidable formulas whose fragments are of the form $ XY …

Avoidability of formulas with two variables

P Ochem, M Rosenfeld - International Conference on Developments in …, 2016 - Springer
In combinatorics on words, a word w over an alphabet\varSigma is said to avoid a pattern p
over an alphabet\varDelta of variables if there is no factor f of w such that f= h (p) where …

On some interesting ternary formulas

P Ochem, M Rosenfeld - International Conference on Combinatorics on …, 2017 - Springer
We show that, up to renaming of the letters, the only infinite ternary words avoiding the
formula ABCAB. ABCBA. ACB. BAC (resp. ABCA. BCAB. BCB. CBA) have the same set of …

[HTML][HTML] Avoidance bases for formulas with reversal

JD Currie, L Mol, N Rampersad - Theoretical Computer Science, 2018 - Elsevier
In the interest of studying formulas with reversal of high avoidability index, we find n-
avoidance bases for formulas with reversal for n∈{1, 2, 3}. We demonstrate that there is a …

A family of formulas with reversal of arbitrarily high avoidability index

P Ochem - Theoretical Computer Science, 2021 - Elsevier
A family of formulas with reversal of arbitrarily high avoidability index - ScienceDirect Skip to
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Avoiding conjugacy classes on the 5-letter alphabet

G Badkobeh, P Ochem - RAIRO-Theoretical Informatics and …, 2020 - rairo-ita.org
We construct an infinite word w over the 5-letter alphabet such that for every factor f of w of
length at least two, there exists a cyclic permutation of f that is not a factor of w. In other …