Talk:One-class classification

Contradiction?

The opening sentence,

One-class classification, also known as unary classification, tries to distinguish one class of objects from all other possible objects

seems self-contradictory and doesn't make sense from a set theory standpoint. Is one-class classifier a misnomer? Distinguishing "one class of objects" from "all other possible objects" defines two sets. Think of a Venn diagram with just one circle. The circle divides the superset plane (all objects) in two: inside the circle and outside the circle. The objective in classification is to determine where the boundaries between sets - the circles - lie on the plane and so determine to which set points on the plane should be assigned.

Perhaps a better name would be one boundary classifier? --p.r.newman (talk) 11:39, 30 April 2013 (UTC)[reply]

Yes, IMHO

Agreed. A unary classifier attempts to classify an instance as belonging to the class or not belonging to the class. There is no assumption of mutual-exclusivity with respect to some class of "all other objects". In the set-theoretic terms, regardless of whether an object belongs to a given subset of the universe, it will always belong to the universe.

So I'd say this is a fundamental mis-representation which should be addressed, by careful rephrasing.

--Justin Washtell