Regular expressions into finite automata
Theoretical Computer Science
One-unambiguous regular languages
Information and Computation
Derivatives of Regular Expressions
Journal of the ACM (JACM)
Two Complete Axiom Systems for the Algebra of Regular Events
Journal of the ACM (JACM)
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
Regular expression types for XML
ACM Transactions on Programming Languages and Systems (TOPLAS)
Ambiguity in Graphs and Expressions
IEEE Transactions on Computers
Inclusion Test Algorithms for One-Unambiguous Regular Expressions
Proceedings of the 5th international colloquium on Theoretical Aspects of Computing
The equivalence problem for regular expressions with squaring requires exponential space
SWAT '72 Proceedings of the 13th Annual Symposium on Switching and Automata Theory (swat 1972)
The inclusion problem for regular expressions
Journal of Computer and System Sciences
Almost-linear inclusion for XML regular expression types
ACM Transactions on Database Systems (TODS)
| Hi-index | 0.00 |
This paper presents a new polynomial-time algorithm for the inclusion problem for certain pairs of regular expressions. The algorithm is not based on construction of finite automata, and can therefore be faster than the lower bound implied by the Myhill-Nerode theorem. The algorithm automatically discards unnecessary parts of the right-hand expression. In these cases the right-hand expression might even be 1-ambiguous. For example, if r is a regular expression such that any DFA recognizing r is very large, the algorithm can still, in time independent of r, decide that the language of ab is included in that of (a+r)b. The algorithm is based on a syntax-directed inference system. It takes arbitrary regular expressions as input, and if the 1-ambiguity of the right-hand expression becomes a problem, the algorithm will report this.