PVASS Reachability is Decidable
Logic in Computer Science
2026-02-19 v2 Formal Languages and Automata Theory
Abstract
Reachability in pushdown vector addition systems with states (PVASS) is among the longest standing open problems in Theoretical Computer Science. We show that the problem is decidable in full generality. Our decision procedure is similar in spirit to the KLMST algorithm for VASS reachability, but works over objects that support an elaborate form of procedure summarization as known from pushdown reachability.
Cite
@article{arxiv.2504.05015,
title = {PVASS Reachability is Decidable},
author = {Roland Guttenberg and Eren Keskin and Roland Meyer},
journal= {arXiv preprint arXiv:2504.05015},
year = {2026}
}
Comments
70 pages, submitted to LICS 2026