Nixon diamond

The Nixon diamond ( engl: Nixon diamond ) refers to a well-known example scenario from artificial intelligence. It serves mostly to illustrate consistency preserving knowledge processing, occasionally including the clarification of different knowledge representation mechanisms.

Term

The term is due to the graphical representation of the scenario, which resembles a rhombus. He comes from English, in the " diamond" for both the "hash" as well as " diamond " is. Because of these multiple meaning " Nixon diamond" is sometimes incorrectly translated as " Nixon diamond ".

Scenario

Given the following initial knowledge:

Interpretation

Classical logic

If we as sets of classical propositional or understand the above statements predicate logic, we can see from the 1st and 3rd conclude that Nixon is a pacifist. On the other hand, we can see from the 2nd and 4th conclude that Nixon is not a pacifist. The shared knowledge is so contradictory, the corresponding logical theory inconsistent.

Nonmonotonic interpretation

Alternatively to the above view, it is obvious to regard the last two sentences as prototypical rules that merely describe a typical pattern. This can be " normally " underline by the adverb:

Such an interpretation provides two different consistent world views, which allow a statement about Nixon's tendency to pacifism: In a Nixon is a pacifist, which can be justified by Nixon's Quakerism and Quaker pacifism typical. In the other Nixon is not a pacifist, which can be justified by Nixon's Republican tilt and the Republican - typical anti- pacifism. Possible inconsistent world views in which Nixon is a pacifist and non- pacifist simultaneously, are usually not considered.