The LSV seminar takes place on Tuesday at 11:00 AM. The usual location is the conference room at Pavillon des Jardins (venue). If you wish to be informed by e-mail about upcoming seminars, please contact Stéphane Le Roux and Matthias Fuegger.
The seminar is open to public and does not require any form of registration.
The reachability problem for vector addition systems with states (VASS) is shown PSPACE-complete when the dimension is two. This improves on a previously known doubly-exponential time bound established by Howell, Rosier, Huynh and Yen in 1986. The coverability and boundedness problems are also noted to be PSPACE-complete. Some complexity results are also given for the reachability problem in two-dimensional VASS and in integer VASS when numbers are encoded in unary.