A number is a data that express a quantity or magnitude. There exist a lot of numeric types but the most important are Naturals $ \textstyle \mathbb{N} $, Integers $ \textstyle \mathbb{Z} $, Rationals $ \textstyle \mathbb{Q} $ and Reals $ \textstyle \mathbb{R} $. However, ontology languages often only use integers (<code>int</code>) and reals (<code>float</code>).

Numbers have order and this can be used to compute simlarities or distances.

Similarity functions Edit