This paper studies the nonterminal complexity of tree controlled grammars. It is proved that the number of nonterminals in tree controlled grammars without erasing rules leads to an infinite hierarchy of families of tree controlled languages, while every recursively enumerable language can be generated by a tree controlled grammar with erasing rules and at most nine nonterminals. © 2011 Elsevie...

For tabled Lindenmayer systems and their languages, the degree of synchronization and the degree of nondeterminism are well investigated measures of descriptional complexity. In this paper the sequential counterparts of tabled Lindenmayer systems, namely cooperating distributed grammar systems and their pure variant (working in the so called t-mode of derivation) are treated with respect to the...

Given an undirected graph and pairs of terminals theRestricted Vertex Multicut problem asks for a minimum set of nonterminal vertices whose removal disconnects each pair of terminals. The problem is known to be NP-complete for trees and polynomial-time solvable for interval graphs. In this paper we give a polynomial-time algorithm for the problem on permutation graphs. Furthermore we show that ...

This paper presents new models for all recursive enumerable languages. These models are based on multigenerative grammar systems that simultaneously generate several strings in a parallel way. The components of these models are context -free grammars, working in a leftmost way. The rewritten nonterminals are determined by a finite set of nonterminal sequences.

myths are reflective of human concerns and needs during ancient times. by reviewing them, it turns out that many human problems today, have a historical background. among the main themes of ancient mythologies, fertility and reproduction have various representations in ancient civilizations. the purpose of this paper was to review myths and common symbols of fertility and reproduction in ancien...

Expression NonTerminal Expression

An updated version of the dust radiation transfer code sunrise, including models for star-forming regions and a self-consistent calculation of the spatially dependent dust and PAH emission, is presented. Given a hydrodynamic simulation of a galaxy, this model can calculate a realistic 2-dimensional ultraviolet– submillimeter spectral energy distribution of the galaxy, including emission lines f...

mother archetype is one of the most important archetypes in carl gustav jung's theory manifested in literary works both as the character of a real mother or in the form of symbols that indicate maternal aspect. epic is a work derived from the male-dominated society in which the heroic functions and masculine power grabs the attentions always more than the women's presence and role. ho...