Talk:Prolog/Constraint Logic Programming

Double Senses and Abuse of Monotonicity
Also there is a big problem right now with the notion "monotonicity". It has different senses. For example here Markus Triska was using monotonicity in respect of the facts of a knowledge base, what should happen with answers when new facts are added.

This property can be depicted as follows:

KB |- A ==> KB + D |- A

So if I add a delta D to the knowledge base, then still at least the same consequences hold as before. Unfortunately Ulrich Neumerkel uses another sense of "monotonicity" in connection with CLP(FD). He refers to the Prolog variables and not to facts.

Typical example being:

?- X = 1, \+ X == 1. false.

?- \+ X == 1, X = 1. true

But as one can easily see in the above example, no adding or removing of facts is involved. So its something else. And if one digs deeper its indeed something elss. RTFM about SLDNF and you will understand that it has to do with variable scoping.

So a big big mess has been created over the last years by Ulrich Neumerkel and others, especially in connection with CLP(FD).

Janburse (discuss • contribs) 10:40, 24 May 2016 (UTC)