,
Diego Figueira
,
Piotr Hofman
Creative Commons Attribution 3.0 Unported license
We study languages of unambiguous VASS, that is, Vector Addition Systems with States, whose transitions read letters from a finite alphabet, and whose acceptance condition is defined by a set of final states (i.e., the coverability language). We show that the problem of universality for unambiguous VASS is ExpSpace-complete, in sheer contrast to Ackermann-completeness for arbitrary VASS, even in dimension 1. When the dimension d ∈ ℕ is fixed, the universality problem is PSpace-complete if d ≥ 2, and coNP-hard for 1-dimensional VASSes (also known as One Counter Nets).
@InProceedings{czerwinski_et_al:LIPIcs.CONCUR.2020.36,
author = {Czerwi\'{n}ski, Wojciech and Figueira, Diego and Hofman, Piotr},
title = {{Universality Problem for Unambiguous VASS}},
booktitle = {31st International Conference on Concurrency Theory (CONCUR 2020)},
pages = {36:1--36:15},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-160-3},
ISSN = {1868-8969},
year = {2020},
volume = {171},
editor = {Konnov, Igor and Kov\'{a}cs, Laura},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2020.36},
URN = {urn:nbn:de:0030-drops-128486},
doi = {10.4230/LIPIcs.CONCUR.2020.36},
annote = {Keywords: unambiguity, vector addition systems, universality problems}
}