Grouped partial ET0L systems and parallel multiple context-free grammars
A relation between ET0L systems and parallel multiple context-free grammars (PMCFGs) is considered. It is shown that there is a subclass of PMCFGs which is equivalent to the family of EDT0L systems. it is also shown that the family of PMCFLs (languages generated by PMCFGs) and the family of ET0L languages are mutually incomparable. A new extension of ET0L systems, grouped partial ET0L systems is defined in order to characterize PMCFLs. There is a subfamily of grouped partial EDT0L languages which coincides with the family of PMCFLs, (C) 2000 Elsevier Science B.V. All rights reserved.
et0l system string rewriting parallel context-free grammar