To define the FSP re-labeling, hiding and interface operators, which can be applied to processes and composite processes, we first describe the meaning of re-labeling and hiding in the underlying LTS model.
Re-labeling applies a relation over action labels R L × L, to an LTS P = < S, A, Δ, q > such that:
where
B1 = {a ∈ A|a′.(a, a′) ∈ R},
B2 = {a′|a ∈ A.(a, a′) ∈ R},
Δ1 = {(p, a, p′) ∈ Δ|a ∈ B1}, and
Δ2 = {(p, a′, p′)|(p, a, p′) ∈ Δ1 (a, a′) ∈ R}.
The set of actions B Act are hidden in the LTS P\B, where P = < S, A, Δ, q >.
If P = Π then P\B = Π otherwise
P\B =< S, (A–B) ∪ {τ}, Δ, q >
where Δ is the smallest relation satisfying the rule:
Let a ∈ Act in
Re-labeling /:
lts(E/ R) = lts(E)/R. lts((Q1 || ... || Qn)/ R) = lts(Q1)/R || ... || lts(Qn)/R
Hiding\:
lts(E\B) = lts(E)\B.
Interface @:
lts(E@ I) = lts(E)\B where B = α(lts(E)) – I.