Query:

Answer:

Model:

Justification: Expand All+1-1Collapse All

• reachable(a) :-
  • in(d,a) :-
    • edge(d,a),
    • proved(edge(d,a)).
  • reachable(d) :-
    • in(b,d) :-
      • edge(b,d),
      • proved(edge(b,d)).
    • reachable(b) :-
      • in(a,b) :-
        • edge(a,b),
        • proved(edge(a,b)).
• global_constraint :-
  • not o_chk_1 :-
    • proved(in(a,b)),
    • edge(a,c),
    • ex(a,c) :-
      • proved(edge(a,c)).
    • edge(b,c),
    • ex(b,c) :-
      • proved(edge(b,c)).
    • proved(in(b,d)),
    • edge(c,d),
    • ex(c,d) :-
      • proved(edge(c,d)).
    • proved(in(d,a)).
  • not o_chk_2 :-
    • proved(in(a,b)),
    • proved(in(b,d)),
    • proved(in(d,a)).