A database language for sets, lists and tables
Information Systems
Safety of recursive Horn clauses with infinite relations
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Pattern matching by Rs-operations: towards a unified approach to querying sequenced data
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Mappings of languages by two-tape devices
Journal of the ACM (JACM)
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
PALM - A Pattern Language for Molecular Biology
Proceedings of the 1st International Conference on Intelligent Systems for Molecular Biology
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Sequences, Datalog and transducers
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Using acceptors as transducers
Theoretical Computer Science
Query Languages for Sequence Databases: Termination and Complexity
IEEE Transactions on Knowledge and Data Engineering
Implementing a Declarative String Query Language with String Restructuring
PADL '99 Proceedings of the First International Workshop on Practical Aspects of Declarative Languages
Using Acceptors as Transducers
WIA '98 Revised Papers from the Third International Workshop on Automata Implementation
How to Make SQL Stand for String Query Language
DBPL '99 Revised Papers from the 7th International Workshop on Database Programming Languages: Research Issues in Structured and Semistructured Database Programming
Unification with Sequence Variables and Flexible Arity Symbols and Its Extension with Pattern-Terms
AISC '02/Calculemus '02 Proceedings of the Joint International Conferences on Artificial Intelligence, Automated Reasoning, and Symbolic Computation
Approximate pattern matching and transitive closure logics
Theoretical Computer Science
Approximate Pattern Matching is Expressible in Transitive Closure Logic
LICS '00 Proceedings of the 15th Annual IEEE Symposium on Logic in Computer Science
Finding paths with the right cost
STACS'99 Proceedings of the 16th annual conference on Theoretical aspects of computer science
Safety, translation and evaluation of alignment calculus
ADBIS'97 Proceedings of the First East-European conference on Advances in Databases and Information systems
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In order to enable the database programmer to reason about relations over strings of arbitrary length we introduce alignment logic, a modal extension of relational calculus. In addition to relations, a state in the model consists of a two-dimensional array where the strings are aligned on top of each other. The basic modality in the language (a transpose, or “slide”) allows for a rearrangement of the alignment, and more complex formulas can be formed using a syntax reminiscent of regular expressions, in addition to the usual connectives and quantifiers. It turns out that the computational counterpart of the string-based portion of the logic is the class of multitape two-way finite state automata, which are devices particularly well suited for the implementation of string matching. A computational counterpart of the full logic is obtained from relational algebra by extending the selection operator into filters based on these multitape machines. Safety of formulas in alignment logic implies that new strings generated from old ones have to be of bounded length. While an undecidable property in general, this boundedness is decidable for an important subclass of formulas. As far as expressive power is concerned, alignment logic includes previous proposals for querying string databases, and gives full Turing computability. The language can be restricted to define exactly regular sets and sets in the polynomial hierarchy.