Question is about a paper "A Block-sorting Lossless Data Compression Algorithm" by M. Burrows and D.J. Wheeler In the paper A Block-sorting Lossless Data Compression Algorithm by M. Burrows and D.J. Wheeler Link.
On page number 5. please describe this line


  If the original string $S$ is of the form $Z^p$ for some substring $Z$ and some $p &gt; 1$, then the sequence $T^i[I]$ for $i = 0,...., N - 1$ will also be of the form $Z'^p$ for some subsequence $Z'$.
F.e. string "abc" becomes "bca" after BWT. This means that "abcabc" will transform into "bbccaa", i.e. "external repetition" of entire string will lead to "internal repetition" of each char in transformed string.