Multiagent Systems

Prof. Dr. Jürgen Dix · Department of Informatics, TUC Multiagent Systems, WS 06/07 648/731
9. Agents based on FOL 4. (Con-)Golog
We define a regression operator R which transforms a
formula of the situation calculus and reduces the nesting
of do(α, do(. . .)) terms by 1.
Definition 9.18 (Regression operator R)
1 If A is not a fluent (incl. . =) or A = Poss(a, s),
then R[A] = A
2 If F is a fluent and s a situation variable or
s = S 0 , then R[F (⃗t, s)] = F (⃗t, s).
3 If F is a fluent with successor state axiom
Poss(a, s) ⊃ [F (x 1 , . . . , x n , do(a, s)) ≡ Φ F ],
then R[F (t 1 , . . . , t n , do(α, σ))] = Φ F | x 1,...,x n ,a,s
t 1 ,...,t n ,α,σ .