Isa and instance relationships

Two attributes isa and instance play an important role in many aspects of knowledge representation.

The reason for this is that they support property inheritance.

isa

-- used to show class inclusion, e.g. isa(mega_star,rich).

instance

-- used to show class membership, e.g. instance(prince,mega_star).

From the above it should be simple to see how to represent these in predicate logic.