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Artificial Intelligence
Descriptive Approach to Language - Theoretic Complexity
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Structural Properties of XPath Fragments
ICDT '03 Proceedings of the 9th International Conference on Database Theory
A Proof System for Finite Trees
CSL '95 Selected Papers from the9th International Workshop on Computer Science Logic
First-Order Logic with Two Variables and Unary Temporal
LICS '97 Proceedings of the 12th Annual IEEE Symposium on Logic in Computer Science
Conditional XPath, the first order complete XPath dialect
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Conjunctive queries over trees
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Efficient algorithms for processing XPath queries
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Semantic characterizations of navigational XPath
ACM SIGMOD Record
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
Conjunctive queries over trees
Journal of the ACM (JACM)
Two-variable logic on data trees and XML reasoning
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Processing queries on tree-structured data efficiently
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Journal of Computer and System Sciences
Tight lower bounds for query processing on streaming and external memory data
Theoretical Computer Science
Polynomial time fragments of XPath with variables
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Static analysis of XML processing with data values
ACM SIGMOD Record
Data & Knowledge Engineering
ACM Computing Surveys (CSUR)
Applying model-checking to solve queries on semistructured data
Computer Languages, Systems and Structures
How big must complete XML query languages be?
Proceedings of the 12th International Conference on Database Theory
Two-variable logic on data trees and XML reasoning
Journal of the ACM (JACM)
Satisfiability of downward XPath with data equality tests
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
An Automata-Theoretic Approach to Regular XPath
DBPL '09 Proceedings of the 12th International Symposium on Database Programming Languages
From XQuery to relational logics
ACM Transactions on Database Systems (TODS)
Journal of Logic, Language and Information
Efficient and expressive tree filters
FSTTCS'07 Proceedings of the 27th international conference on Foundations of software technology and theoretical computer science
Two-variable logic and key constraints on data words
Proceedings of the 14th International Conference on Database Theory
Interpreting tree-to-tree queries
ICALP'06 Proceedings of the 33rd international conference on Automata, Languages and Programming - Volume Part II
Satisfiability of XPath queries with sibling axes
DBPL'05 Proceedings of the 10th international conference on Database Programming Languages
Automata and logics for words and trees over an infinite alphabet
CSL'06 Proceedings of the 20th international conference on Computer Science Logic
Regular languages with variables on graphs
Information and Computation
Decidability of Downward XPath
ACM Transactions on Computational Logic (TOCL)
ICALP'07 Proceedings of the 34th international conference on Automata, Languages and Programming
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We give two sufficient conditions on XPath like languages for having first order expressivity, meaning that every first order definable set of paths in an ordered node-labeled tree is definable in that XPath language. They are phrased in terms of expansions of navigational (sometimes called “Core”) XPath. Adding either complementation, or the more elegant conditional paths is sufficient. A conditional path is an axis relation of the form (one_step_axis::n[F])+, denoting the transitive closure of the relation expressed by one_step_axis::n[F]. As neither is expressible in navigational XPath we also give characterizations in terms of first order logic of the answer sets and the sets of paths navigational XPath can define. The first in terms of a suitable two variable fragment, the second in terms of unions of conjunctive queries.