Theory of computation: formal languages, automata, and complexity
Theory of computation: formal languages, automata, and complexity
Finding regular simple paths in graph databases
VLDB '89 Proceedings of the 15th international conference on Very large data bases
Algorithms for finding patterns in strings
Handbook of theoretical computer science (vol. A)
Tree automata, Mu-Calculus and determinacy
SFCS '91 Proceedings of the 32nd annual symposium on Foundations of computer science
Finding Regular Simple Paths in Graph Databases
SIAM Journal on Computing
Time-space tradeoffs for undirected graph traversal by graph automata
Information and Computation
Minimal Ascending and Descending Tree Automata
SIAM Journal on Computing
On the use of regular expressions for searching text
ACM Transactions on Programming Languages and Systems (TOPLAS)
Regular expressions with nested levels of back referencing form a hierarchy
Information Processing Letters
GraphLog: a visual formalism for real life recursion
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
View-based query processing for regular path queries with inverse
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Perl: The Programmer's Companion
Perl: The Programmer's Companion
CSL '02 Proceedings of the 16th International Workshop and 11th Annual Conference of the EACSL on Computer Science Logic
UnQL: a query language and algebra for semistructured data based on structural recursion
The VLDB Journal — The International Journal on Very Large Data Bases
On the power of tree-walking automata
Information and Computation - Special issue: ICC '99
A Graph Query Language and Its Query Processing
ICDE '99 Proceedings of the 15th International Conference on Data Engineering
Reasoning on regular path queries
ACM SIGMOD Record
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
The expressivity of XPath with transitive closure
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Finite automata and their decision problems
IBM Journal of Research and Development
Weighted path queries on semistructured databases
Information and Computation
Pattern expressions and pattern automata
Information Processing Letters
On the equivalence, containment, and covering problems for the regular and context-free languages
Journal of Computer and System Sciences
Automata- and logic-based pattern languages for tree-structured data
Proceedings of the 2nd international conference on Semantics in databases
Programming Python
First order paths in ordered trees
ICDT'05 Proceedings of the 10th international conference on Database Theory
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This paper presents a pattern language based on regular expressions that allows the introduction of variables that can be instantiated to portions of the path that matches the expression. The paper will define a simple syntax for the language and its formal semantics. It will also study a modification of finite state automata that, through the introduction of actions on transitions, allows the variables to be instantiated while matching the expression. Finally, the paper will show that the problem of answering queries with variables is inherently harder than simple matching, essentially because, even for fairly simple expressions, the size of the results can be exponential in the size of the graph. The class of expressions and a class of graphs for which query answering is polynomial will be identified, and a processing algorithm for these expressions based on the intersection graph will be provided and analyzed.