,
Corto Mascle
,
Patrick Totzke
Creative Commons Attribution 4.0 International license
We provide a new algebraic technique to solve the sequential flow problem in polynomial space. The task is to maximise the flow through a graph where edge capacities can be changed over time by choosing a sequence of capacity labelings from a given finite set. Our method is based on a novel factorization theorem for finite semigroups that, applied to a suitable flow semigroup, allows to derive small witnesses. This generalises to multiple in/output vertices, as well as regular constraints.
@InProceedings{gimbert_et_al:LIPIcs.ICALP.2026.98,
author = {Gimbert, Hugo and Mascle, Corto and Totzke, Patrick},
title = {{Optimal Sequential Flows}},
booktitle = {53rd International Colloquium on Automata, Languages, and Programming (ICALP 2026)},
pages = {98:1--98:18},
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.2026.98},
URN = {urn:nbn:de:0030-drops-264875},
doi = {10.4230/LIPIcs.ICALP.2026.98},
annote = {Keywords: Network Flow, Sequential Flow, Semigroup Factorization}
}