4 results
Wojciech Czerwiński ; Piotr Hofman ; SŁawomir Lasota.
This paper is about reachability analysis in a restricted subclass of multi-pushdown automata. We assume that the control states of an automaton are partially ordered, and all transitions of an automaton go downwards with respect to the order. We prove decidability of the reachability problem, and […]
Published on September 11, 2013
Dmitry Chistikov ; Wojciech Czerwiński ; Piotr Hofman ; Michał Pilipczuk ; Michael Wehar.
We show that any one-counter automaton with $n$ states, if its language is non-empty, accepts some word of length at most $O(n^2)$. This closes the gap between the previously known upper bound of $O(n^3)$ and lower bound of $\Omega(n^2)$. More generally, we prove a tight upper bound on the length of […]
Published on March 5, 2019
Piotr Hofman ; Slawomir Lasota ; Richard Mayr ; Patrick Totzke.
One-counter nets (OCN) are finite automata equipped with a counter that can store non-negative integer values, and that cannot be tested for zero. Equivalently, these are exactly 1-dimensional vector addition systems with states. We show that both strong and weak simulation preorder on OCN are […]
Published on March 14, 2016
Piotr Hofman ; Jakub Różycki.
Following a recently considered generalisation of linear equations to unordered-data vectors and to ordered-data vectors, we perform a further generalisation to data vectors that are functions from k-element subsets of the unordered-data set to vectors of integer numbers. These generalised equations […]
Published on December 12, 2022