Forbidding ET0L grammars

Simple Semi-conditional Et0l Grammars

The present contribution introduces and studies simple semi-conditional ET0L grammars (SSC-ET0L grammars for short). It is demonstrated that SSC-ET0L grammars with permitting and forbidding conditions of length no more than one and two, respectively, generate all the family of recursively enumerable languages; if erasing productions are not allowed, these grammars generate precisely the family ...

Descriptional Complexity of Generalized Forbidding Grammars

This paper discusses the descriptional complexity of generalized forbidding grammars in context of degrees, numbers of nonterminals and conditional productions, and a new descriptional complexity measure—an index—of generalized forbidding grammars.

Adding Global Forbidding Context to Context-Free Grammars

Remarks on Regulated Limited ET0L Systems and Regulated Context-Free Grammars

We continue the studies of the second author on regulated uniformly k-limited and regulated k-limited ET0L systems. We focus on the permitting and forbidding random context regulation. Especially, we establish some results on (regulated) propagating (uniformly) k-limited ET0L systems which were not solved in 2, 18, 21, 22]. Moreover, relations to recurrent programmed languages introduced by von...

Forbidding Rainbow-colored Stars

We consider an extremal problem motivated by a paper of Balogh [J. Balogh, A remark on the number of edge colorings of graphs, European Journal of Combinatorics 27, 2006, 565–573], who considered edge-colorings of graphs avoiding fixed subgraphs with a prescribed coloring. More precisely, given r ≥ t ≥ 2, we look for n-vertex graphs that admit the maximum number of r-edge-colorings such that at...