Definition Edit

Given a set of ontological entities O, a similarity function is a function \sigma:O\times O \longrightarrow \mathbb{R}^+ that associates to every pair of entities of O, a real number that express the resemblance between the entities, and such that holds the following properties:

  • Non-negativity: \forall x,y \in O, \sigma(x,y)\geq 0
  • Maximality: \forall x,y \in O, \sigma(x,x)\geq \sigma(x,y)

Some authors add to this list this other property:

  • Simmetry: \forall x,y\in O, \sigma(x,y) = \sigma(y,x)

In the same way, it is possible to define the dual concept of dissimiarity function as a function \delta:O\times O \longrightarrow \mathbb{R}^+, that express the difference between two entities, with the following properties:

  • Non-negativity \forall x,y \in O, \sigma(x,y)\geq 0
  • Minimality: \forall x\in O, \delta(x,x)= 0

A (dis)similarity function is normalized if their range is the real interval [0,1].

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.