Michael Benedikt, Stefan Göller, Stefan Kiefer, Andrzej S. Murawski. Bisimilarity of Pushdown Automata is Nonelementary. In 28th Annual ACM/IEEE Symposium on Logic in Computer Science, LICS 2013, New Orleans, LA, USA, June 25-28, 2013. pages 488-498, IEEE Computer Society, 2013. [doi]
Abstract is missing.