Lifting above-theory to situation calculus, cont.

asserting that block A is on block B in a specific situation S0, and we want to derive ist(c,above(A,B,S0)). We proceed as follows. First use (4) to get

Now we enter c1(S0) and get

From (3) and (7) we conclude

from which entering c1(S0) gives

(10) and (12) give

holding in context c1(S0). We can now either continue reasoning in c1(S0) or leave c1(S0) and get

and using (5)

and finally