We study two-player games of infinite duration that are played on finite or infinite game graphs. A winning strategy for such a game is positional if it only depends on the current position, and not on the history of the play. A game is positionally determined if, from each position, one of the two players has a positional winning strategy. The theory of such games is well studied for winning c...

It is shown that bisimulation equivalence is decidable for the processes generated by (nondeterministic) pushdown automata where the pushdown behaves like a counter. Also niteness up to bisimilarity is shown to be decidable for the mentioned processes. 3

Queues, stacks, and tapes are basic concepts which have direct applications in compiler design and the general design of algorithms. Whereas stacks (pushdown store or last-in-rst-out storage) have been thoroughly investigated and are well understood, this is much less the case for queues ((rst-in-rst-out storage). In this paper we present a comprehensive study comparing queues to stacks and tap...

This paper introduces the model of priced timed pushdown systems as an extension of discrete-timed pushdown systems with a cost model that assigns multidimensional costs to both transitions and stack symbols. For this model, we consider the minimal cost reachability problem: i.e., given a priced timed pushdown system and a target set of configurations, determine the minimal possible cost of any...

We study two-player games of infinite duration that are played on finite or infinite game graphs. A winning strategy for such a game is positional if it only depends on the current position, and not on the history of the play. A game is positionally determined if, from each position, one of the two players has a positional winning strategy. The theory of such games is well studied for winning c...

Given two pushdown systems, the bisimilarity problem asks whether they are bisimilar. While this problem is known to be decidable our main result states that it is nonelementary, improving EXPTIME-hardness, which was the previously best known lower bound for this problem. Our lower bound result holds for normed pushdown systems as well.

In this paper, we introduce and study a variant of regulated pushdown automata, called blackhole state-controlled R-PDA where a symbol can always be pushed to the pushdown, but only a given depth of the pushdown contents is remembered; the rest of the pushdown contents is lost. In addition, the automaton can check the form of its pushdown contents according to a given control language. We prese...

A method is presented for obtaining a simple deterministic pushdown transducer which acts as a parser for simple chain grammars. It is shown that a simple deterministic grammar can be constructed which covers the simple chain grammar. To obtain both the simple deterministic pushdown transducer and the cover result, a new type of parse is introduced which differs from the left and right-parses w...

The Web is increasingly understood as a global information space consisting not just of linked documents, but also of Linked Data. More than just a vision, the resulting Web of Data has been brought into being by the maturing of the Semantic Web technology stack, and by the publication of an increasing number of data sets according to the principles of Linked Data. The Linked Data on the Web (L...