Theoretical Computer Science
POPL '95 Proceedings of the 22nd ACM SIGPLAN-SIGACT symposium on Principles of programming languages
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
Verifying lossy channel systems has nonprimitive recursive complexity
Information Processing Letters
CSL '02 Proceedings of the 16th International Workshop and 11th Annual Conference of the EACSL on Computer Science Logic
Undecidable problems in unreliable computations
Theoretical Computer Science - Latin American theoretical informatics
Finite state machines for strings over infinite alphabets
ACM Transactions on Computational Logic (TOCL)
Two-Variable Logic on Words with Data
LICS '06 Proceedings of the 21st Annual IEEE Symposium on Logic in Computer Science
LTL with the Freeze Quantifier and Register Automata
LICS '06 Proceedings of the 21st Annual IEEE Symposium on Logic in Computer Science
Graph Reachability and Pebble Automata over Infinite Alphabets
LICS '09 Proceedings of the 2009 24th Annual IEEE Symposium on Logic In Computer Science
On Pebble Automata for Data Languages with Decidable Emptiness Problem
MFCS '09 Proceedings of the 34th International Symposium on Mathematical Foundations of Computer Science 2009
A Note on Two-pebble Automata Over Infinite Alphabets
Fundamenta Informaticae - Bridging Logic and Computer Science: to Johann A. Makowsky for his 60th birthday
Automata and logics for words and trees over an infinite alphabet
CSL'06 Proceedings of the 20th international conference on Computer Science Logic
Expressive power of pebble automata
ICALP'06 Proceedings of the 33rd international conference on Automata, Languages and Programming - Volume Part I
Consistency of XML specifications
Inconsistency Tolerance
On notions of regularity for data languages
FCT'07 Proceedings of the 16th international conference on Fundamentals of Computation Theory
Graph Reachability and Pebble Automata over Infinite Alphabets
ACM Transactions on Computational Logic (TOCL)
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In this paper we study a subclass of pebble automata (PA) for data languages for which the emptiness problem is decidable. Namely, we show that the emptiness problem for weak 2-pebble automata is decidable, while the same problem for weak 3-pebble automata is undecidable. We also introduce the so-called top view weak PA. Roughly speaking, top view weak PA are weak PA where the equality test is performed only between the data values seen by the two most recently placed pebbles. The emptiness problem for this model is still decidable. It is also robust: alternating, non-deterministic and deterministic top view weak PA have the same recognition power; and are strong enough to accept all data languages expressible in Linear Temporal Logic with the future-time operators, augmented with one register freeze quantifier.