On the Number of Non-equivalent Parameterized Squares in a String
摘要
A string s is called a parameterized square when \(s = xy\) for strings x, y and x and y are parameterized equivalent. Kociumaka et al. showed the number of parameterized squares, which are non-equivalent in parameterized equivalence, in a string of length n that contains \(\sigma \) distinct characters is at most \(2 \sigma ! n\) [TCS 2016]. In this paper, we show that the maximum number of non-equivalent parameterized squares is less than \(\sigma n\) , which significantly improves the best-known upper bound by Kociumaka et al.