Zenoness for Timed Pushdown Automata
  Timed pushdown automata are pushdown automata extended with a finite set of real-valued clocks. Additionaly, each symbol in the stack is equipped with a value representing its age. The enabledness of a transition may depend on the values of the clocks and the age of the topmost symbol. Therefore, dense-timed pushdown automata subsume both pushdown automata and timed automata. We have previously shown that the reachability problem for this model is decidable. In this paper, we study the zenoness problem and show that it is EXPTIME-complete. 
Parosh Aziz Abdulla (Uppsala University), Mohamed Faouzi Atig (Uppsala   University), Jari Stenman (Uppsala University)
cs.FL