Collapse Operation Increases Expressive Power of Deterministic Higher Order Pushdown Automata

Pawel Parys (1)

1 MIMUW - Faculty of Mathematics, Informatics, and Mechanics [Warsaw]

We show that collapsible deterministic second level pushdown automata can recognize more languages than deterministic second level pushdown automata (without collapse). This implies that there exists a tree generated by a second level recursion scheme which is not generated by any second level safe recursion scheme.

Mots clés: Formal Languages

Domaines: Complexité [cs.CC]; Algorithme et structure de données [cs.DS]

Pawel Parys. Collapse Operation Increases Expressive Power of Deterministic Higher Order Pushdown Automata. Symposium on Theoretical Aspects of Computer Science (STACS2011), Mar 2011, Dortmund, Germany. pp.603-614. ⟨hal-00573593⟩