Handbook of formal languages, vol. 1
Ultimate-Definite and Symmetric-Definite Events and Automata
Journal of the ACM (JACM)
The Design and Analysis of Computer Algorithms
The Design and Analysis of Computer Algorithms
Computing forbidden words of regular languages
Fundamenta Informaticae - Special issue on computing patterns in strings
Regular expressions: new results and open problems
Journal of Automata, Languages and Combinatorics
Decision Problems for Convex Languages
LATA '09 Proceedings of the 3rd International Conference on Language and Automata Theory and Applications
Introduction to Algorithms, Third Edition
Introduction to Algorithms, Third Edition
On NFAs where all states are final, initial, or both
Theoretical Computer Science
Space-bounded reducibility among combinatorial problems
Journal of Computer and System Sciences
Multiple-entry finite automata
Journal of Computer and System Sciences
A note on multiple-entry finite automata
Journal of Computer and System Sciences
Quotient complexity of ideal languages
Theoretical Computer Science
Quotient Complexity of Closed Languages
Theory of Computing Systems
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We examine decision problems for various classes of convex languages, previously studied by Ang and Brzozowski, originally under the name ''continuous languages''. We can decide whether a language L is prefix-, suffix-, factor-, or subword-convex in polynomial time if L is represented by a DFA, but these problems become PSPACE-complete if L is represented by an NFA. If a regular language is not convex, we find tight upper bounds on the length of the shortest words demonstrating this fact, in terms of the number of states of an accepting DFA. Similar results are proved for some subclasses of convex languages: the prefix-, suffix-, factor-, and subword-closed languages, and the prefix-, suffix-, factor-, and subword-free languages. Finally, we briefly examine these questions where L is represented by a context-free grammar.