Results on NLC grammars with one-letter terminal alphabets

Abstract

Node-label controlled graph grammars (NLC grammars) are a mechanism to generate sets of graphs (called graph languages). This paper examines the generating power of NLC grammars with a restricted connection relation and some closure properties of the class of NLC languages. Also, a modified language generating mechanism for NLC grammars is introduced, and the resulting class of graph languages is compared to the class of NLC languages. All results are based on grammars with one-letter terminal alphabets.