Contextual Grammars with Subregular Choice
Jürgen Dassow · Fundamenta Informaticae · 2004
We discuss external contextual grammars with choice where the choice language belongs to a family of subregular languages. We determine the hierarchy of language families of contextual languages which is obtained by the use of nilpotent, combinational, definite, regular suffix closed, and regular commutative languages as choice languages.