ON CYCLICALLY OVERLAP-FREE WORDS IN BINARY ALPHABETS

We shall be concerned with avoidable patterns of words on two symbols, a and b. The pattern we are interested in is overlapness: a word x avoids overlapping or is overlap-free if it has no two occurrences of a factor that overlap each other. For example the word aababaa does not avoid overlapping since it contains the factor aba in two occurrences such that these have a common part.