ON CONTEXT-FREE REWRITING WITH A SIMPLE RESTRICTION AND ITS COMPUTATIONAL COMPLETENESS

Th is p ap e r d iscu sses c ont e x t - free r ewrit in g sy st ems inwh ich t h e re ex ist two d isjoint fi n it e set s of ru les, an d a sy mb ol, r e-ferred t o as a con d it ion of ap p licab ility, is at t ach ed t o each ru le ineither of these two sets. I n one set, a rule wit h a sy mb ol attach ed toit is ap p licab le if t h e at t ach ed sy mb ol o ccu rs in t h e c u rrent rewrit t e nst rin g wh ile in t h e ot h er set , su ch a r u le is ap p licab le if t h e at t ach edsy mb ol do es not o ccu r there. The present p ap er demonstrates thatthese rewriting sy stems are computationally complete. From this mainresu lt , t h e p ap e r d erives seve ral c on seq u en ces an d solves seve ral op e nprob lems