scholarly journals Representing recursively enumerable languages by iterated deletion

2004 ◽  
Vol 314 (3) ◽  
pp. 451-457 ◽  
Author(s):  
Michael Domaratzki ◽  
Alexander Okhotin
Keyword(s):  
Recursively Enumerable ◽  
Recursively Enumerable Languages

COMPUTING WITH MEMBRANES (P SYSTEMS): A VARIANT

2000 ◽  
Vol 11 (01) ◽  
pp. 167-181 ◽  
Author(s):  
GHEORGHE PĂUN
Keyword(s):  
Membrane Computing ◽  
P Systems ◽  
Open Problems ◽  
Recursively Enumerable ◽  
Pass Through ◽  
The One ◽  
Priority Relation ◽  
Recursively Enumerable Languages ◽  
Biochemical Features ◽  
Computing Models

Membrane Computing is a recently introduced area of Molecular Computing, where a computation takes place in a membrane structure where multisets of objects evolve according to given rules (they can also pass through membranes). The obtained computing models were called P systems. In basic variants of P systems, the use of objects evolution rules is regulated by a given priority relation; moreover, each membrane has a label and one can send objects to precise membranes, identified by their labels. We propose here a variant where we get rid of both there rather artificial (non-biochemical) features. Instead, we add to membranes and to objects an "electrical charge" and the objects are passed through membranes according to their charge. We prove that such systems are able to characterize the one-letter recursively enumerable languages (equivalently, the recursively enumerable sets of natural numbers), providing that an extra feature is considered: the membranes can be made thicker or thinner (also dissolved) and the communication through a membrane is possible only when its thickness is equal to 1. Several open problems are formulated.

Probabilistic Semi–Simple Splicing System and Its Characteristics

2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Mathuri Selvarajoo ◽  
Fong Wan Heng ◽  
Nor Haniza Sarmin ◽  
Sherzod Turaev
Keyword(s):  
Regular Languages ◽  
Computational Power ◽  
Dna Molecules ◽  
Finite Sets ◽  
Generative Power ◽  
Recursively Enumerable ◽  
Splicing Systems ◽  
Recursively Enumerable Languages

The concept of splicing system was first introduced by Head in 1987. This model has been introduced to investigate the recombinant behavior of DNA molecules. Splicing systems with finite sets of axioms only generate regular languages. Hence, different restrictions have been considered to increase the computational power up to the recursively enumerable languages. Recently, probabilistic splicing systems have been introduced where probabilities are initially associated with the axioms, and the probability of a generated string is computed by multiplying the probabilities of all occurrences of the initial strings in the computation of the string. In this paper, some properties of probabilistic semi-simple splicing systems, which are special types of probabilistic splicing systems, are investigated. We prove that probabilistic semi-simple splicing systems can also increase the generative power of the generated languages.

scholarly journals On representing recursively enumerable languages by internal contextual languages

1998 ◽  
Vol 205 (1-2) ◽  
pp. 61-83 ◽  
Author(s):  
Andrzej Ehrenfeucht ◽  
Gheorghe P↑n ◽  
Grzegorz Rozenberg
Keyword(s):  
Recursively Enumerable ◽  
Recursively Enumerable Languages

scholarly journals A homomorphic characterization of recursively enumerable languages

1985 ◽  
Vol 35 ◽  
pp. 261-269 ◽  
Author(s):  
Sadaki Hirose ◽  
Satoshi Okawa ◽  
Masaaki Yoneda
Keyword(s):  
Recursively Enumerable ◽  
Recursively Enumerable Languages

scholarly journals Derivation "Trees" and Parallelism in Chomsky-Type Grammars

Triangle ◽  
2018 ◽  
pp. 101
Author(s):  
Benedek Nagy
Keyword(s):  
Formal Language ◽  
Phrase Structure ◽  
Formal Language Theory ◽  
Language Theory ◽  
Context Sensitive ◽  
Recursively Enumerable ◽  
Rule Set ◽  
Context Free ◽  
Recursively Enumerable Languages ◽  
Context Free Grammars

In this paper we discuss parallel derivations for context-free, contextsensitive and phrase-structure grammars. For regular and linear grammars only sequential derivation can be applied, but a kind of parallelism is present in linear grammars. We show that nite languages can be generated by a recursion-free rule-set. It is well-known that in context-free grammars the derivation can be in maximal (independent) parallel way. We show that in cases of context-sensitive and recursively enumerable languages the parallel branches of the derivation have some synchronization points. In the case of context-sensitive grammars this synchronization can only be local, but in a derivation of an arbitrary grammar we cannot make this restriction. We present a framework to show how the concept of parallelism can be t to the derivations in formal language theory using tokens.

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