72 Chapter 3 DevelopingKnowleDge-BaseDsystems
This enables us to give some general sentences over those possible in
propositional logic:
∀x.Man(x) ⇒Mortal(x). All men are mortal.
∀x∃y.Father(x,y). Every man has a father.
First-order logic is powerful and expressive. However, such a high degree
of expression sometimes complicates the process of inference. Also, it is not
possible to represent generalized knowledge, such as “Sweety eats everything
that she likes.” It is difficult to mention each thing that Sweety likes in a few
rules. First-order logic may not be helpful in creating references to other
sentences; hence, high-order logic is required.
3.13 REPRESENTING PROCEDURAL KNOWLEDGE
Procedural knowledge represents how to reach a solution ...