kind_von(karl_VI, leopold_I).
kind_von(maria_theresia, karl_VI).
kind_von(joseph_II, maria_theresia).
kind_von(joseph_II, franz_I).
kind_von(leopold_II, maria_theresia).
kind_von(marie_antoinette, maria_theresia).
:- kind_von(Kind, Elternteil).
:- kind_von(joseph_II, friedrich_II).
! Zusicherung gescheitert
----- n599 ------------------------
Goals that do not succeed are reported as errors.
In this case the predicate is correct
(Joseph's II father is Franz I and not Friedrich II) -
and the goal should not succeed.
With :/- instead of :-
we state that a goal should fail.
The non standard operator :/-
is used to prevent premature usage of negation.
Change :- to :/-
and press ![[DO]](DO.gif)
.
[logprog|GUPU|UWN]