Illustration of the proof of Theorem 3.

Shown are two aligned copies of the section of the reference sequence where (black) represents the sequence between two equivalent deletions (green) and (magenta). The filled polygon illustrates the sequence identity that holds if and only if and are equivalent. Following the grey arrows up and down and from left to right, it can be seen that the sequence section consists of repeats of the deletion sequence until the last copy overlaps with the deletion sequence .