Name
Abstract | ||
|---|---|---|
An infinite square-free word w over the alphabet Σ3 = {0, 1, 2} is said to have a k-stem σ if |σ| = k and w = σw1w2$\\dots$ where for each i, there exists a permutation πi of Σ3 which extended to a morphism gives wi = πiσ. Harju proved that there exists an infinite k-stem word for k = 1, 2, 3, 9 and 13 ≤ k ≤ 19, but not for 4 ≤ k ≤ 8 and 10 ≤ k ≤ 12. He asked whether k-stem words exist for each k ≥ 20. We give a positive answer to this question. Currie has found another construction that answers Harju's question. |
Year | DOI | Venue |
|---|---|---|
2014 | 10.3233/FI-2014-1035 | Fundam. Inform. |
Keywords | Field | DocType |
permutations,morphism,mathematical proofs,mathematical formulas | Discrete mathematics,Combinatorics,Square-free integer,Existential quantification,Permutation,Prefix,Mathematical proof,Mathematics,Morphism,Alphabet | Journal |
Volume | Issue | ISSN |
132 | 1 | 0169-2968 |
Citations | PageRank | References |
0 | 0.34 | 2 |
Authors | ||
1 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Pascal Ochem | 1 | 258 | 36.91 |