Handbook of formal languages, vol. 1
Commutativity in free inverse monoids
Theoretical Computer Science - Special issue: papers dedicated to the memory of Marcel-Paul Schützenberger
Automata, Languages, and Machines
Automata, Languages, and Machines
Theory of Codes
A defect theorem for bi-infinite words
Theoretical Computer Science
On Defect Effect of Bi-Infinite Words
MFCS '98 Proceedings of the 23rd International Symposium on Mathematical Foundations of Computer Science
On the Decomposition of Finite Languages
On the Decomposition of Finite Languages
The Branching Point Approach to Conway's Problem
Formal and Natural Computing - Essays Dedicated to Grzegorz Rozenberg [on occasion of his 60th birthday, March 14, 2002]
The Commutation with Codes and Ternary Sets of Words
STACS '03 Proceedings of the 20th Annual Symposium on Theoretical Aspects of Computer Science
FCT '01 Proceedings of the 13th International Symposium on Fundamentals of Computation Theory
Combinatorial and Computational Problems on Finite Sets of Words
MCU '01 Proceedings of the Third International Conference on Machines, Computations, and Universality
The branching point approach to Conway's problem
Formal and natural computing
A simple undecidable problem: the inclusion problem for finite substitutions on ab*c
Information and Computation
On the complexity of decidable cases of the commutation problem of languages
Theoretical Computer Science
Theoretical Computer Science - The art of theory
Regular solutions of language inequalities and well quasi-orders
Theoretical Computer Science - Automata, languages and programming: Algorithms and complexity (ICALP-A 2004)
Theoretical Computer Science - In honour of Professor Christian Choffrut on the occasion of his 60th birthday
Theoretical Computer Science
Conjugacy of finite biprefix codes
Theoretical Computer Science
On language inequalities XK ⊆ LX
DLT'05 Proceedings of the 9th international conference on Developments in Language Theory
The power of commuting with finite sets of words
STACS'05 Proceedings of the 22nd annual conference on Theoretical Aspects of Computer Science
Finite sets of words and computing
MCU'04 Proceedings of the 4th international conference on Machines, Computations, and Universality
| Hi-index | 5.23 |
We prove that given a set X of two nonempty words, a set Y of nonempty words commutes with X if and only if either Y is a union of powers of X or X,Yt+ for some primitive word t. We also show that the same holds for certain special types of codes, but does not hold, in general, for sets of cardinality at least 4.