Dense-choice Counter Machines revisited

This paper clarifies the picture about Dense-choice Counter Machines, which have been less studied than (discrete) Counter Machines. We revisit the definition of "Dense Counter Machines" so that it now extends (discrete) Counter Machines, and we provide new undecidability and decidability results. Using the first-order additive mixed theory of reals and integers, we give a logical characterization of the sets of configurations reachable by reversal-bounded Dense-choice Counter Machines

Verification for Timed Automata extended with Unbounded Discrete Data Structures

We study decidability of verification problems for timed automata extended with unbounded discrete data structures. More detailed, we extend timed automata with a pushdown stack. In this way, we obtain a strong model that may for instance be used to model real-time programs with procedure calls. It is long known that the reachability problem for this model is decidable. The goal of this paper is to identify subclasses of timed pushdown automata for which the language inclusion problem and related problems are decidable

Reachability in Timed Counter Systems

We introduce Timed Counter Systems, a new class of systems mixing clocks and counters. Such systems have an infinite state space, and their reachability problems are generally undecidable. By abstracting clock values with a Region Graph, we show the Counter Reachability Problem to be decidable for three subclasses: Timed VASS, Bounded Timed Counter Systems, and Reversal-Bounded Timed Counter Systems

Reachability in Timed Counter Systems

We introduce Timed Counter Systems, a new class of systems mixing clocks and counters. Such systems have an infinite state space, and their reachability problems are generally undecidable. By abstracting clock values with a Region Graph, we show the Counter Reachability Problem to be decidable for three subclasses: Timed VASS, Bounded Timed Counte