test.pl

% coloring

adjacent(1, 2).
adjacent(1, 3).
adjacent(1, 4).
adjacent(1, 5).
adjacent(2, 1).
adjacent(2, 3).
adjacent(2, 4).
adjacent(3, 1).
adjacent(3, 2).
adjacent(3, 4).
adjacent(4, 1).
adjacent(4, 2).
adjacent(4, 3).
adjacent(4, 5).
adjacent(5, 1).
adjacent(5, 4).


color(1, red,    a).
color(2, blue,   a).
color(3, green,  a).
color(4, yellow, a).
color(5, blue,   a).

conflict(Coloring) :-
    adjacent(X, Y),
    color(X, Color, Coloring),
    color(Y, Color, Coloring).


% children
child(A, B).
child(B, C).
child(B, D).
child(B, E).
child(C, F).
child(G, H).

grandchild(X, Y) :-
    child(X, Z),
    child(Z, Y).

ancestor(X, Y) :-
    child(X, Y).

ancestor(X, Y) :-
    child(X, Z),
    decendant(Z, Y).