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A slightly more complex logic:
ALH
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Like Ex, it operates on “individuals” and “classes”
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But it also have “roles”: binary relations on individuals
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It also has two special symbols: ⊤ and ⊥ (more or less for
“true” and “false”)
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ALH also allows more relationships for axioms:
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A ⊓ B and ⌝A for classes (and also
A ⊏ B, like in Ex )
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- intersection and negation of classes, respectively
- If R is a role, then A ≣ ∀R.C or B
≣ ∃R.⊤ are also possible
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- defining classes by restrictions, ie, “all values must be in
C”, and “there must be at least one value”