%0 Journal Article %T Serializing the Parallelism in Parallel Communicating Pushdown Automata Systems %A M. Sakthi Balan %J Electronic Proceedings in Theoretical Computer Science %D 2009 %I Open Publishing Association %R 10.4204/eptcs.3.5 %X 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. %U http://arxiv.org/pdf/0907.5083v1