An example

Consider the following:

• Prince is a mega star.
• Mega stars are rich.
• Rich people have fast cars.
• Fast cars consume a lot of petrol.

and try to draw the conclusion:

Prince's car consumes a lot of petrol.

So we can translate Prince is a mega star into:

mega_star(prince)

and Mega stars are rich into:

m: mega_star(m) rich(m)

Rich people have fast cars, the third axiom is more difficult:

• Is cars a relation and therefore car(c,m) says that case is m's car. OR
• Is cars a function? So we may have car_of(m).

Assume cars is a relation then axiom 3 may be written:

c,m: car(c,m)rich(m) fast(c).

The fourth axiom is a general statement about fast cars.

Let consume(c) mean that car consumes a lot of petrol.

Then we may write:

c: fast(c) m:car(c,m) consume(c) .

Is this enough?

NO! - Does prince have a car?

We need the car_of function after all (and addition to car):

c:car(car_of(m),m).

The result of applying car_of to is 's car.

The final set of predicates is:

mega_star(prince)

m: mega_star(m) rich(m)

c:car(car_of(m),m).

c,m: car(c,m) rich(m) fast(c).

c: fast(c) m:car(c,m) consume(c) .

Given this we could conclude:

consume(car_of(prince)).