Intuitively, if two strings S1 and S2 are sufficiently similar and we already have an FM-index for S1 then, by storing a little extra information, we should be able to reuse parts of that index in an FM-index for S2. We formalize this intuition and show that it can lead to significant space savings in practice, as well as to some interesting theoretical problems.
Cite
@article{arxiv.1404.4814,
title = {Reusing an FM-index},
author = {Djamal Belazzougui and Travis Gagie and Simon Gog and Giovanni Manzini and Jouni Sirén},
journal= {arXiv preprint arXiv:1404.4814},
year = {2014}
}