Displaying similar documents to “Equality sets for recursively enumerable languages”

Closure properties of hyper-minimized automata

Andrzej Szepietowski (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

Two deterministic finite automata are almost equivalent if they disagree in acceptance only for finitely many inputs. An automaton is hyper-minimized if no automaton with fewer states is almost equivalent to . A regular language is canonical if the minimal automaton accepting is hyper-minimized. The asymptotic state complexity () of a regular language is the number of states of a hyper-minimized automaton for a language finitely different from . In this paper we show...

Closure properties of hyper-minimized automata

Andrzej Szepietowski (2012)

RAIRO - Theoretical Informatics and Applications

Similarity:

Two deterministic finite automata are almost equivalent if they disagree in acceptance only for finitely many inputs. An automaton is hyper-minimized if no automaton with fewer states is almost equivalent to . A regular language is canonical if the minimal automaton accepting is hyper-minimized. The asymptotic state complexity () of a regular language is the number of states of a hyper-minimized automaton...

Regularity of languages defined by formal series with isolated cut point

Alberto Bertoni, Maria Paola Bianchi, Flavi D’Alessandro (2012)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

Let  = { ∈  | ()  } be the language recognized by a formal series :  → ℝ with isolated cut point . We provide new conditions that guarantee the regularity of the language in the case that is rational or is a Hadamard quotient of rational series. Moreover the decidability property of such conditions is investigated.

On Conjugacy of Languages

Julien Cassaigne, Juhani Karhumäki, Ján Maňuch (2010)

RAIRO - Theoretical Informatics and Applications

Similarity:

We say that two languages and are conjugates if they satisfy the for some language . We study several problems associated with this equation. For example, we characterize all sets which are conjugated a two-element biprefix set , as well as all two-element sets which are conjugates.

Linear size test sets for certain commutative languages

Štěpán Holub, Juha Kortelainen (2010)

RAIRO - Theoretical Informatics and Applications

Similarity:

We prove that for each positive integer the finite commutative language = ( ...) possesses a test set of size at most Moreover, it is shown that each test set for has at least -1 elements. The result is then generalized to commutative languages containing a word such that (i) alph() = alph}(); and (ii) each symbol ∈ alph}() occurs at least twice in if it occurs at least twice in some word of : each such possesses...

Integers in number systems with positive and negative quadratic Pisot base

Z. Masáková, T. Vávra (2014)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

We consider numeration systems with base and − , for quadratic Pisot numbers and focus on comparing the combinatorial structure of the sets Z and Z of numbers with integer expansion in base , resp. − . Our main result is the comparison of languages of infinite words and coding the ordering of distances between consecutive - and (− )-integers. It turns out that for a class of roots of − − , the languages coincide, while for other...

An aperiodicity problem for multiwords

Véronique Bruyère, Olivier Carton, Alexandre Decan, Olivier Gauwin, Jef Wijsen (2012)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

Multiwords are words in which a single symbol can be replaced by a nonempty set of symbols. They extend the notion of partial words. A word is in a multiword if it occurs in word that can be obtained by selecting one single symbol among the symbols provided in each position of . Motivated by a problem on incomplete databases, we investigate a variant of the pattern matching problem which is to decide whether a word is certain in a multiword . We study the language CERTAIN() of multiwords...

Complexity of infinite words associated with beta-expansions

Christiane Frougny, Zuzana Masáková, Edita Pelantová (2010)

RAIRO - Theoretical Informatics and Applications

Similarity:

We study the complexity of the infinite word associated with the Rényi expansion of in an irrational base . When is the golden ratio, this is the well known Fibonacci word, which is Sturmian, and of complexity . For such that is finite we provide a simple description of the structure of special factors of the word . When =1 we show that . In the cases when or max} we show that the first difference of the complexity function takes value in for every , and consequently we determine...

Undecidability of infinite post correspondence problem for instances of size 8

Jing Dong, Qinghui Liu (2012)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

The infinite Post Correspondence Problem (PCP) was shown to be undecidable by Ruohonen (1985) in general. Blondel and Canterini [36 (2003) 231–245] showed that PCP is undecidable for domain alphabets of size 105, Halava and Harju [40 (2006) 551–557] showed that PCP is undecidable for domain alphabets of size 9. By designing a special coding, we delete a letter from Halava and Harju’s construction. So we prove that PCP is undecidable for domain alphabets of size 8.