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I have read W3C documents, but I don't understand why they are different. I'll give the definitions of them in W3C documents:

Here is also a difference: One difference with functional properties is that for inverse-functional properties no additional object-property or datatype-property axiom is required: inverse-functional properties are by definition object properties. You can see these words in the IFP link above.

But I don't understand it, can you give me a detailed explanation?

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Xinze LYU
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1 Answers1

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Stating that property f is functional means that, for an individual x, there is only one value for f.

So, given:

x f p
x f q

A reasoner will infer that p and q are the same individual, or the same literal.

Inverse functional means that the inverse of f is functional, i.e.,

x f a
y f a

Is like

a r x
a r y

Where r is functional, and the inverse of f. The reasoner can infer that x and y are the same individual (so this time the subjects are inferred to be identical).

This is also the reason for inverse properties to be object properties. If you pick a data property, you cannot have an inverse for it, because you cannot have a literal as subject of a statement.

Ignazio
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  • @ciferlv Please accept the answer if you deem it correct. – Sentry Feb 28 '17 at 06:46
  • @Ignazio OK, this is my first time to use stackoverflow, I am a litter unfamiliar with it. – Xinze LYU Feb 28 '17 at 06:59
  • @Ignazio Excuse me, do you know some something about OAEI, Instance Matching or Alignment Format? Can you help me about this question? The link is http://stackoverflow.com/questions/42502101/how-to-use-alignment-api-to-generate-a-alignment-format-file Thank you. – Xinze LYU Feb 28 '17 at 07:04