Ahmed Bouajjani, 2026-03-30

Decidability result on Reachability

  • undecidable : exTSO, Power
  • decidable: TSO, PSO, TSO+Persistency, k-alternation bounded exTSO

The proof is done by reduction to well structured systems

  • well quasi order (WQO) on state space
  • monotonicity of transition relation w.r.t. to WQO

For TSO:

  • Lossy channel systems
  • Dual TSO with load buffers