Revisiting reachability in Polynomial Interrupt Timed Automata

Abstract

Polynomial Interrupt Timed Automata (PolITA) are finite automata with clocks organized along hierarchical levels. These clocks are equipped with an interruption mechanism, well suited to the modeling of real-time operating systems. Moreover, transitions between states contain polynomial guards and updates. The reachability problem in this class is known to be in 2EXPTIME with a decision procedure based on the cylindrical algebraic decomposition. We improve this complexity to EXPSPACE mainly using a combinatorial argument and we include a reduction leading to a PSPACE lower bound.