
(* Los problem *)

theory LosProblem

  type t
  predicate p t t
  predicate q t t

  (* p and q are transitive *)
  axiom p_trans: forall x y z: t. p x y -> p y z -> p x z
  axiom q_trans: forall x y z: t. q x y -> q y z -> q x z

  (* q is symmetric *)
  axiom q_sym: forall x y: t. q x y -> q y x

  (* p\/q is universal *)
  axiom p_or_q: forall x y: t. p x y \/ q x y

  (* show that either p or q is universal *)
  goal los_problem: (forall x y: t. p x y) \/ (forall x y: t. q x y)

end
