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).
----- n599 ------------------------
Negative goals/assertions can be used to formulate integrity
constraints like Noone is his own child.
:/- kind_von(P, P).
Consider a different program featuring
infinite computations.
[logprog|GUPU|UWN]