master-degree-notes/Concurrent Systems/notes/14.md

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We shall only consider finite processes (processes without recursive definitions)

  • a limited handling of recursion is possible
  • deciding bisimilarity for general processes is undecidable

Inference system = axioms + inference rules

  • soundness: whatever I infer is correct (i.e., bisimiar)
  • completeness: whatever is bisimilar, it can be inferred

Axioms & Rules for Strong Bisimilarity

350 quite obvious.

350 basically we can let the left or the right process evolve, leaving the other unchanged, or they can synchronize.

350

  • if a process does not perform any action, a restriction won't do anything
  • ...

350

P is in standard form if and only if P \triangleq \sum_{i}\alpha_{i}P_{i} and \forall_{i}P_{i} is in standard form.

Lemma: $\forall P \exists P'$* in standard form such that \vdash P = P' Proof: by induction on the structure of P.

Base case: P \triangleq 0. It suffices to consider P' \triangleq 0 and conclude reflexivity. Inductive step: we have to consider three cases.