Reachability in Two-Dimensional Unary Vector Addition Systems with States is NL-Complete

Blondin et al. showed at LICS 2015 that two-dimensional vector addition systems with states have reachability witnesses of length exponential in the number of states and polynomial in the norm of vectors. The resulting guess-and-verify algorithm is optimal (PSPACE), but only if the input vectors are...

Full description

Saved in:
Bibliographic Details
Published inProceedings of the 31st Annual ACM/IEEE Symposium on Logic in Computer Science pp. 477 - 484
Main Authors Englert, Matthias, Lazić, Ranko, Totzke, Patrick
Format Conference Proceeding
LanguageEnglish
Published New York, NY, USA ACM 05.07.2016
SeriesACM Conferences
Online AccessGet full text
ISBN9781450343916
1450343910
DOI10.1145/2933575.2933577

Cover

More Information
Summary:Blondin et al. showed at LICS 2015 that two-dimensional vector addition systems with states have reachability witnesses of length exponential in the number of states and polynomial in the norm of vectors. The resulting guess-and-verify algorithm is optimal (PSPACE), but only if the input vectors are given in binary. We answer positively the main question left open by their work, namely establish that reachability witnesses of pseudo-polynomial length always exist. Hence, when the input vectors are given in unary, the improved guess-and-verify algorithm requires only logarithmic space.
ISBN:9781450343916
1450343910
DOI:10.1145/2933575.2933577