A classify statement is also called a specialization. It specifies that atoms of one concept are atoms of another concept as well. You can use it to buils classifications like Linnaeus did.
Syntax and meaning
In a specialization, e.g. CLASSIFY Sedan ISA Car, we call the first concept (Sedan) the specific concept and the second (Car) the generic concept. The meaning of a specialization is that every atom from the specific concept is an atom from the generic concept as well. So every (atom that is a) Sedan is a Car as well.
So in general: CLASSIFY ISA means: .
Examples
To save some writing, you may specify
This means exactly the same as
Best practice
A specialization is a static relationship. If you want to say that a student is a person, please consider whether you want this to be static. If a person can enroll to become a student, or graduate or drop out to become non-student again, the dynamics of that cannot be captured in a specialization. Use a relationship instead to model the state of being a student.
E.g. RELATION student[Person*Enrollment]
By adding and removing pairs to that relation, it continuously reflects which persons are a student.
A
B
∀a:a∈A⇒a∈B
CLASSIFY <upper case identifier> ISA <upper case identifier>
CLASSIFY Monkey ISA Mammal
CLASSIFY Sedan ISA Car
CLASSIFY Monkey, Cow, Human ISA Mammal
CLASSIFY Monkey ISA Mammal
CLASSIFY Cow ISA Mammal
CLASSIFY Human ISA Mammal