One distinguishes between a Strict Binding which is expressed with universal Quantification and the Open Binding which is expressed with an Existential Quantification.
The Strict Binding binds the Range of Role to a specific Class. On the other hand one has the open Binding also to the Range of a Role to a Class.
Examination ⊑ ∀hasSupervisor.Professor
An Examination must be supervised by a Professor
(∀x)(Examination(x) → ∀hasSupervisor(x,y) → Professor(y)))
Examination ⊑ ∃hasSupervisor.Person
Every Examination has at least one supervisor (who is a person)
(∀x)(Examination(x) → (∃y)(hasSupervisor(x,y) Λ Person(y)))
