Avoidability of Formulas with Two Variables

نویسندگان
چکیده

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

Avoidability of Formulas with Two Variables

In combinatorics on words, a word w over an alphabet Σ is said to avoid a pattern p over an alphabet ∆ of variables 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. We consider the patterns such that at most two variables appear at least twic...

متن کامل

Avoidability of circular formulas

Clark has defined the notion of n-avoidance basis which contains the avoidable formulas with at most n variables that are closest to be unavoidable in some sense. The family Ci of circular formulas is such that C1 = AA, C2 = ABA.BAB, C3 = ABCA.BCAB.CABC and so on. For every i 6 n, the n-avoidance basis contains Ci. Clark showed that the avoidability index of every circular formula and of every ...

متن کامل

On Loop Formulas with Variables

Recently Ferraris, Lee and Lifschitz proposed a new definition of stable models that does not refer to grounding, which applies to the syntax of arbitrary first-order sentences. We show its relation to the idea of loop formulas with variables by Chen, Lin, Wang and Zhang, and generalize their loop formulas to disjunctive programs and to arbitrary first-order sentences. We also extend the syntax...

متن کامل

Extendable formulas in two variables in intuitionistic logic

In this paper we discuss projective, exact and extendable formulas of the intuitionistic propositional calculus IPC. Exact formulas were introduced in [6] as the formulas that axiomatize the theories of substitutions. In an attempt to find a semantic characterization of exact formulas, de Jongh and Visser [7] defined the notion of extendable formulas and proved that every exact formula is exten...

متن کامل

A note on the avoidability of binary patterns with variables and reversals

In this note we present a characterisation of all unary and binary patterns that do not only contain variables, but also reversals of their instances. These types of variables were studied recently in either more general or particular cases. We show that the results are not surprising at all in the general case, and extend the avoidability of these patterns to enforce aperiodic words.

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: The Electronic Journal of Combinatorics

سال: 2017

ISSN: 1077-8926

DOI: 10.37236/6536