Doubled Patterns with Reversal and Square-Free Doubled Patterns

نویسندگان

چکیده

In combinatorics on words, a word $w$ over an alphabet $\Sigma$ is said to avoid pattern $p$ $\Delta$ if there no factor $f$ of such that $f=h(p)$ where $h:\Delta^*\to\Sigma^*$ non-erasing morphism. A be $k$-avoidable exists infinite $k$-letter avoids $p$. \emph{doubled} every variable occurs at least twice. Doubled patterns are known $3$-avoidable. Currie, Mol, and Rampersad have considered generalized notion which allows occurrences reversed. That is, $h(V^R)$ the mirror image $h(V)$ for $V\in\Delta$. We show doubled with reversal also conjecture (classical) do not contain square $2$-avoidable. confirm this most 4 variables. This implies $p$, growth rate ternary words avoiding square-free words. previous version paper containing only first result has been presented WORDS 2021.

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Doubled Patterns are 3-Avoidable

In combinatorics on words, a word w over an alphabet Σ is said to avoid a pattern p over an alphabet ∆ if there is no factor f of w such that f = h(p) where h : ∆∗ → Σ∗ is a non-erasing morphism. A pattern p is said to be k-avoidable if there exists an infinite word over a k-letter alphabet that avoids p. A pattern is said to be doubled if no variable occurs only once. Doubled patterns with at ...

متن کامل

Optimal carbon tax doubled

Typically, cost–benefit analysis (CBA) has suggested ‘optimal’ carbon tax regimes that result in a global temperature rise of around 3 °C, or even eventually (post-2100) 4 °C, above preindustrial levels. However, risk analysis approaches indicate that these levels of temperature rise result in climate change impacts that pose a high or very high level of risk to society and ecosystems1 (Fig. 1)...

متن کامل

On the doubled tetrus

This paper describes some properties of a certain fibered hyperbolic 3manifold which arises ”in nature”; that is, as the cover of a closed manifold constructed by other means. Among other things, the main theorem answers in the affirmative the question of whether it is possible for a fibered hyperbolic manifold to be a double across a connected surface. (We first heard this question from Alan R...

متن کامل

Doubled quadratic division algebras

The concept of doubling, introduced around 1840 by Hamilton and Graves, associates with any quadratic algebra A over a field k of characterstic not 2 its double V(A) = A×A, with multiplication (w, x)(y, z) = (wy− z̄x, xȳ + zw). It yields an endofunctor on the category of all quadratic k-algebras which is faithful but not full. We study in which respect the division property of a quadratic k-alge...

متن کامل

Doubled Geometry and T-Folds

The doubled formulation of string theory, which is T-duality covariant and enlarges spacetime with extra coordinates conjugate to winding number, is reformulated and its geometric and topological features examined. It is used to formulate string theory in T-fold backgrounds with T-duality transition functions and a quantum implementation of the constraints of the doubled formalism is presented....

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Electronic Journal of Combinatorics

سال: 2023

ISSN: ['1077-8926', '1097-1440']

DOI: https://doi.org/10.37236/11590