Automata for reduction properties solving
Journal of Symbolic Computation
Separation Logic: A Logic for Shared Mutable Data Structures
LICS '02 Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science
Towards Regular Languages over Infinite Alphabets
MFCS '01 Proceedings of the 26th International Symposium on Mathematical Foundations of Computer Science
A Spatial Logic for Querying Graphs
ICALP '02 Proceedings of the 29th International Colloquium on Automata, Languages and Programming
Equality and Disequality Constraints on Direct Subterms in Tree Automata
STACS '92 Proceedings of the 9th Annual Symposium on Theoretical Aspects of Computer Science
The Decidability of Model Checking Mobile Ambients
CSL '01 Proceedings of the 15th International Workshop on Computer Science Logic
XDuce: A statically typed XML processing language
ACM Transactions on Internet Technology (TOIT)
CDuce: an XML-centric general-purpose language
ICFP '03 Proceedings of the eighth ACM SIGPLAN international conference on Functional programming
TQL: a query language for semistructured data based on the ambient logic
Mathematical Structures in Computer Science
Tree automata with one memory set constraints and cryptographic protocols
Theoretical Computer Science - Automata, languages and programming
Expressiveness of a Spatial Logic for Trees
LICS '05 Proceedings of the 20th Annual IEEE Symposium on Logic in Computer Science
Two-variable logic on data trees and XML reasoning
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Expressiveness and complexity of graph logic
Information and Computation
Unranked tree automata with sibling equalities and disequalities
ICALP'07 Proceedings of the 34th international conference on Automata, Languages and Programming
Tree Automata with Global Constraints
DLT '08 Proceedings of the 12th international conference on Developments in Language Theory
More expressive extensions of TQL
CSTST '08 Proceedings of the 5th international conference on Soft computing as transdisciplinary science and technology
LATA '09 Proceedings of the 3rd International Conference on Language and Automata Theory and Applications
Rigid tree automata and applications
Information and Computation
Applying tree languages in proof theory
LATA'12 Proceedings of the 6th international conference on Language and Automata Theory and Applications
Hi-index | 0.00 |
We investigate in this paper the spatial logic TQL for querying semistructured data, represented as unranked ordered trees over an infinite alphabet. This logic consists of usual Boolean connectives, spatial connectives (derived from the constructors of a tree algebra), tree variables and a fixpoint operator for recursion. Motivated by XML-oriented tasks, we investigate the guarded TQL fragment. We prove that for closed formulas this fragment is MSO-complete. In presence of tree variables, this fragment is strictly more expressive than MSO as it allows for tree (dis)equality tests, i.e. testing whether two subtrees are isomorphic or not. We devise a new class of tree automata, called TAGED, which extends tree automata with global equality and disequality constraints. We show that the satisfiability problem for guarded TQL formulas reduces to emptiness of TAGED. Then, we focus on bounded TQL formulas: intuitively, a formula is bounded if for any tree, the number of its positions where a subtree is captured by a variable is bounded. We prove this fragment to correspond with a subclass of TAGED, called bounded TAGED, for which we prove emptiness to be decidable. This implies the decidability of the bounded guarded TQL fragment. Finally, we compare bounded TAGED to a fragment of MSO extended with subtree isomorphism tests.