We propose a new pumping technique for 2-dimensional vector addition systems with states (2-VASS) building on natural geometric properties of runs. We illustrate its applicability by reproving an exponential bound on the length of the shortest accepting run, and by proving a new pumping lemma for languages of 2-VASS. The technique is expected to be useful for settling questions concerning languages of 2-VASS, e.g., for establishing decidability status of the regular separability problem.
Cite
@article{arxiv.1906.10494,
title = {New Pumping Technique for 2-dimensional VASS},
author = {Wojciech Czerwiński and Sławomir Lasota and Christof Löding and Radosław Piórkowski},
journal= {arXiv preprint arXiv:1906.10494},
year = {2019}
}