2,450 research outputs found
Introducing the Concept of Activation and Blocking of Rules in the General Framework for Regulated Rewriting in Sequential Grammars
We introduce new possibilities to control the application of rules based on
the preceding application of rules which can be de ned for a general model of sequential
grammars and we show some similarities to other control mechanisms as graph-controlled
grammars and matrix grammars with and without applicability checking as well as gram-
mars with random context conditions and ordered grammars. Using both activation and
blocking of rules, in the string and in the multiset case we can show computational com-
pleteness of context-free grammars equipped with the control mechanism of activation
and blocking of rules even when using only two nonterminal symbols
One-Membrane P Systems with Activation and Blocking of Rules
We introduce new possibilities to control the application of rules based on
the preceding applications, which can be de ned in a general way for (hierarchical) P
systems and the main known derivation modes. Computational completeness can be
obtained even for one-membrane P systems with non-cooperative rules and using both
activation and blocking of rules, especially for the set modes of derivation.
When we allow the application of rules to in
uence the application of rules in previous
derivation steps, applying a non-conservative semantics for what we consider to be a
derivation step, we can even \go beyond Turing"
On the Degree of Extension of Some Models Defining Non-Regular Languages
This work is a survey of the main results reported for the degree of
extension of two models defining non-regular languages, namely the context-free
grammar and the extended automaton over groups. More precisely, we recall the
main results regarding the degree on non-regularity of a context-free grammar
as well as the degree of extension of finite automata over groups. Finally, we
consider a similar measure for the finite automata with translucent letters and
present some preliminary results. This measure could be considered for many
mechanisms that extend a less expressive one.Comment: In Proceedings AFL 2023, arXiv:2309.0112
Networks of picture processors
Abstract
The goal of this work is to survey in a systematic and uniform way the main results regarding different computational aspects of networks of picture processors viewed as rectangular picture accepting devices. We first consider networks with evolutionary picture processors only and discuss their computational power as well as a partial solution to the picture matching problem.
Two variants of these networks, which are differentiated by the protocol of communication, are also surveyed: networks with filtered connections and networks with polarized processors. Then we consider networks having both types of processors, i.e., evolutionary processors and hiding
processors, and provide a complete solution to the picture matching problem. Several results which follow from this solution are then presented. Finally we discuss some possible directions for further research
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