Building Source Complete Plans

movie-hut(X, Y) -> title-time(X, Y), title-actor(X, Z)

house-of-movies($X, Y) -> title-time(X, Y), title-actor(X, Z)

title-time(X, Y) :- dom(X), house-of-movies(X, Y)

<X, f2(X, Y)>

title-time(X, Y) :- movie-hut(X, Y)

<X, f1(X, Y)>

[Duschka, Genesereth 97]

title-actor (X, X, Y) :- movie-hut(X, Y)

dom(X) :- movie-hut(X, Y)

dom(Y) :- movie-hut(X, Y)

title-actor (X, X, Y) :- dom(X), house-of-movies(X, Y)

dom(Y) :- dom(X), house-of-movies(X, Y)

query(X, Y) :- title-time(X, Y)

Source Inversion Rules

Binding restrictions lead to recursion in the plan