On a construction of Friedman

Jeffrey Shallit, Ming-wei Wang

Published 2000-09-08Version 1

H. Friedman obtained remarkable results about the longest finite sequence $x$ such that for all $i \not= j$ the word $x[i..2i]$ is not a subsequence of $x[j..2j]$. In this note we consider what happens when ``subsequence'' is replaced by ``subword''.