Serializing the Parallelism in Parallel Communicating Pushdown Automata Systems

TL;DR

This paper introduces a property called known communication for parallel communicating pushdown automata systems, proving that a variant's computational power matches that of multi-head pushdown automata, and characterizes a new subclass as finite intersections of such automata.

Contribution

It defines known communication, proves equivalence of returning centralized PCPA with multi-head pushdown automata, and characterizes simple-RPCPA as finite intersections of these automata.

Findings

RCPCPA has the same power as multi-head pushdown automata

Simple-RPCPA can be expressed as finite intersections of multi-head pushdown automata

Introduces the property of known communication for PCPA systems

Abstract

We consider parallel communicating pushdown automata systems (PCPA) and define a property called known communication for it. We use this property to prove that the power of a variant of PCPA, called returning centralized parallel communicating pushdown automata (RCPCPA), is equivalent to that of multi-head pushdown automata. The above result presents a new sub-class of returning parallel communicating pushdown automata systems (RPCPA) called simple-RPCPA and we show that it can be written as a finite intersection of multi-head pushdown automata systems.