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semantic-webowl

What is General Class Axiom used for?


This post shows an example of General Class Axiom:

((walksLike some Duck) and (talksLike some Duck)) SubClassOf Duck

Isn't it the same as giving a necessary and sufficient condition on Duck?

Duck EquivalentTo: ((walksLike some Duck) and (talksLike some Duck))

Aren't they logically equivalent? I've read this article as well, but I don't understand what General Class Axiom's real use for.


Solution

  • The subsumption provides only one of necessary or sufficient, as AKWS remarked.

    Example:

    A1 instanceOf Duck

    A2 instanceOf (walksLike some Duck) A2 instanceOf (talksLike some Duck)

    With just the subsumption axiom, the queries:

    Instances of Duck: A1, A2 Instances of walksLike some Duck: A2

    With the equivalence axiom:

    Instances of Duck: A1, A2 Instances of walksLike some Duck: A1, A2