,
Roland Guttenberg
,
Łukasz Orlikowski
,
Henry Sinclair-Banks
,
Yangluo Zheng
Creative Commons Attribution 4.0 International license
The geometric dimension g of a Vector Addition System with States (VASS) is the dimension of the vector space generated by cycles in the VASS; this parameter refines the standard dimension d, the number of counters. Recently, it was discovered that the fastest-known algorithm for solving the reachability problem for VASS has the same complexity in terms of g as in terms of d. This suggests that the geometric dimension may in fact be a more adequate parameter for measuring the complexity of VASS reachability problems. We initiate a more systematic study of the geometric dimension. We discuss differences between two parameters: the geometric dimension and the SCC dimension. Our main technical result states that classical results about the coverability and boundedness problems can be improved from dimension d to geometric dimension g. Namely, coverability is witnessed by runs of length n^{2^𝒪(g)} instead of n^{2^𝒪(d)}, and unboundedness can be witnessed by runs of length n^{2^𝒪(g log g)} instead of n^{2^𝒪(d log d)}, where n is the size of the instance. We also study integer reachability and simultaneous unboundedness in VASS parameterised by the geometric dimension.
@InProceedings{czerwinski_et_al:LIPIcs.ICALP.2026.177,
author = {Czerwi\'{n}ski, Wojciech and Guttenberg, Roland and Orlikowski, {\L}ukasz and Sinclair-Banks, Henry and Zheng, Yangluo},
title = {{Exploring VASS Parameterised by Geometric Dimension}},
booktitle = {53rd International Colloquium on Automata, Languages, and Programming (ICALP 2026)},
pages = {177:1--177:25},
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.2026.177},
URN = {urn:nbn:de:0030-drops-265655},
doi = {10.4230/LIPIcs.ICALP.2026.177},
annote = {Keywords: vector addition systems, Petri nets, geometric dimensions, coverability problem, integer reachability problem, simultaneous unboundedness, reachability problem}
}