On space and time efficient TM simulations of some restricted classes of PDA's

Abstract

In this paper we present some space/time efficient Turing machine algorithms for recognizing some subclasses of DCFLs. In particular, we show that the finite minimal stacking and “simple” strict restricted (a subclass of strict restricted) deterministic pushdown automata (FMS-DPDAs, SSR-DPDAs, respectively) can be simulated by offline Turing machines simultaneously in space S(n) and time n²/S(n) for any tape function S(n) satisfying log n ⩽ S(n) ⩽ n which is constructable in n²/S(n) time. Generalizations are then made for the corresponding classes of 2-way DPDAs.