Logarithmic Equal-Letter Runs for BWT of Purely Morphic Words

In this paper we study the number $$r_{\texttt {bwt}}$$ of equal-letter runs produced by Burrows-Wheeler transform (BWT) when it is applied to purely morphic finite words, which are words generated iterating prolongable morphisms. Such a parameter very significant since provides measure performances BWT, in terms both compressibility and indexing. particular, prove that, BWT whichever word on binary alphabet, $$\mathcal {O}(\log n)$$ , where n length word. Moreover, that $$\varTheta (\log for large class These bounds proved providing some new structural properties bispecial circular factors such words.