Square-free Strings Over Alphabet Lists
نویسندگان
چکیده
We solve an open problem that was posed in [GKM10]: Given an alphabet list L = L1, . . . , Ln, where |Li| = 3 and 0 ≤ i ≤ n, can we always find a square-free string, W = W1W2 . . .Wn, where Wi ∈ Li? We show that this is indeed the case. We do so using an “offending suffix” characterization of forced repetitions, and a counting, non-constructive, technique. We discuss future directions related to finding a constructive solution, namely a polytime algorithm for generating square-free words over such lists.
منابع مشابه
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تاریخ انتشار 2015