Decidability of DPDA equivalence

Schema Revisited

Two schema problems from the 1970s are examined, monadic recursion schemes and first-order recursion schemas. Research on these problems halted because they were shown to be equivalent to the problem of decidability of language equivalence between DPDA (deterministic pushdown automata). Recently a decidability proof for equivalence of DPDA was given by Sénizergues [10, 11], which therefore also...

Decision Problems for Deterministic Pushdown Automata on Infinite Words

The article surveys some decidability results for DPDAs on infinite words (ω-DPDA). We summarize some recent results on the decidability of the regularity and the equivalence problem for the class of weak ω-DPDAs. Furthermore, we present some new results on the parity index problem for ωDPDAs. For the specification of a parity condition, the states of the omega-DPDA are assigned priorities (nat...

An Introduction to Decidability of DPDA Equivalence

A Short Decidability Proof for DPDA Language Equivalence via First-Order Grammars

The main aim of the paper is to give a short self-contained proof of the decidability of language equivalence for deterministic pushdown automata, which is the famousproblem solved by G. Sénizergues, for which C. Stirling has derived a primitive recursive complexity upper bound. The proof here is given in the framework of first-order grammars, which seems to be particularly apt for the aim.

Deciding DPDA Equivalence Is Primitive Recursive

Recently Sénizergues showed decidability of the equivalence problem for deterministic pushown automata. The proof of decidability is two semi-decision procedures that do not give a complexity upper bound for the problem. Here we show that there is a simpler deterministic decision procedure that has a primitive recursive upper bound.