,
Markus Lohrey
Creative Commons Attribution 4.0 International license
We study string-to-string functions which are compatible with compression in the following sense: given a compressed representation of an input string, one can compute in polynomial time a compressed representation of the output string. As the compression formalism, we use straight-line programs (i.e. context-free grammars that produce only one string). As the functions, we use finite state transducers, with a focus on the regular and polyregular functions. We show that all regular functions are compatible with compression, but this is no longer true for the polyregular functions. We identify a subclass of the polyregular functions - the so-called rectangular polyregular functions - which is compatible with compression, and we characterise this subclass in terms of a functional programming language.
@InProceedings{bojanczyk_et_al:LIPIcs.ICALP.2026.170,
author = {Boja\'{n}czyk, Miko{\l}aj and Lohrey, Markus},
title = {{Transducers on Compressed Strings}},
booktitle = {53rd International Colloquium on Automata, Languages, and Programming (ICALP 2026)},
pages = {170:1--170:22},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-428-4},
ISSN = {1868-8969},
year = {2026},
volume = {374},
editor = {Bhattacharya, Sayan and Nanongkai, Danupon and Benedikt, Michael and Puppis, Gabriele},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2026.170},
URN = {urn:nbn:de:0030-drops-265580},
doi = {10.4230/LIPIcs.ICALP.2026.170},
annote = {Keywords: polyregular functions, grammar compression}
}