worker(andersson).
worker(pettersson).
worker(lundström).

passenger(handersson).
passenger(hpettersson).
passenger(hlundström).

samename(handersson, andersson).
samename(hpettersson, pettersson).
samename(hlundström, lundström).

lives(hpettersson, gothenburg).
lives(X, stockholm) :- passenger(X), \+lives(X, gothenburg), \+earns3(X).

earns100(hlundström).
earns3(X) :- passenger(X), \+earns100(X).

billiards(andersson).

works_as(braker, X) :- worker(X), samename(Y, X), lives(Y, stockholm).
works_as(driver, X) :- worker(X), \+works_as(braker, X), \+works_as(burner, X).
works_as(burner, X) :- worker(X), \+billiards(X), \+works_as(braker, X).astmatix