Nicolas Markey

Résumé

Reconfigurable broadcast networks provide a convenient formalism for modelling and reasoning about networks of mobile agents broadcasting messages to other agents following some (evolving) communication topology. The parameterized verification of such models aims at checking whether a given property holds irrespective of the initial configuration (number of agents, initial states and initial communication topology). We focus here on the synchronization property, asking whether all agents converge to a set of target states after some execution. This problem is known to be decidable in polynomial time when no constraints are imposed on the evolution of the communication topology (while it is undecidable for static broadcast networks).

In this paper we investigate how various constraints on reconfigurations affect the decidability and complexity of the synchronization problem. In particular, we show that when bounding the number of reconfigured links between two communications steps by a constant, synchronization becomes undecidable; on the other hand, synchronization remains decidable in PTIME when the bound grows with the number of agents.

@inproceedings{tacas2018-2-BBM,
  author =              {Balasubramanian, A. R. and Bertrand, Nathalie and
                         Markey, Nicolas},
  title =               {Parameterized verification of synchronization in
                         constrained reconfigurable broadcast networks},
  editor =              {Beyer, Dirk and Huisman, Marieke},
  booktitle =           {{P}roceedings of the 24th {I}nternational
                         {C}onference on {T}ools and {A}lgorithms for
                         {C}onstruction and {A}nalysis of {S}ystems
                         ({TACAS}'18)~-- {P}art~{II}},
  acronym =             {{TACAS}'18 (Part~{II})},
  publisher =           {Springer-Verlag},
  series =              {Lecture Notes in Computer Science},
  volume =              {10806},
  pages =               {38-54},
  year =                {2018},
  month =               apr,
  doi =                 {10.1007/978-3-319-89963-3_3},
  abstract =            {Reconfigurable broadcast networks provide a
                         convenient formalism for modelling and reasoning
                         about networks of mobile agents broadcasting
                         messages to other agents following some (evolving)
                         communication topology. The parameterized
                         verification of such models aims at checking whether
                         a given property holds irrespective of the initial
                         configuration (number of agents, initial states and
                         initial communication topology). We~focus here on
                         the \emph{synchronization property}, asking whether
                         all agents converge to a set of target states after
                         some execution. This~problem is known to be
                         decidable in polynomial time when no constraints are
                         imposed on the evolution of the communication
                         topology (while~it~is undecidable for static
                         broadcast networks).\par In this paper we
                         investigate how various constraints on
                         reconfigurations affect the decidability and
                         complexity of the synchronization problem.
                         In~particular, we show that when bounding the number
                         of reconfigured links between two communications
                         steps by a constant, synchronization becomes
                         undecidable; on~the other hand, synchronization
                         remains decidable in PTIME when the bound grows with
                         the number of agents.},
}