Important Open Problems

At the Oberwolfach meeting on Combinatorics on Words in 2010, the participants suggested a list of important open problems in the field.

Here is the list:

1. IsPiNormal?

2. KolakoskiFrequencies

3. WordEquationSatisfiability

4. LargestIndependentSystem

5. FraenkelsProblem

6. BrzozowskiConjecture

7. SquarefreeWordEnumeration

8. WordkAvoidable

9. PrimitiveWordsContextFree

10. PCP3Decidable

11. NivatConjecture

12. ReconstructionfromSubwords

13. HHPVProblem

14. SAdicConjecture

15. CodeUniquePrimitiveRoot

16. ExponentofMorphism

17. MatricesGenerateFreeGroup

18. NumberofRightSpecialFactors

-- JeffreyShallit - 13 Oct 2010