One-Unknown Word Equations and Three-Unknown Constant-Free Word Equations

Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9840)


We prove connections between one-unknown word equations and three-unknown constant-free word equations, and use them to prove that the number of equations in an independent system of three-unknown constant-free equations is at most logarithmic with respect to the length of the shortest equation in the system. We also study two well-known conjectures. The first conjecture claims that there is a constant c such that every one-unknown equation has either infinitely many solutions or at most c. The second conjecture claims that there is a constant c such that every independent system of three-unknown constant-free equations with a nonperiodic solution is of size at most c. We prove that the first conjecture implies the second one, possibly for a different constant.


Combinatorics on words Word equations Independent systems 


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© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Computer ScienceKiel UniversityKielGermany
  2. 2.Department of Mathematics and StatisticsUniversity of TurkuTurkuFinland

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