- (Sub)classes can be created by restricting the behavior of a property on that class
        
- (Sub)classes can be created by restricting the behavior of
- a property on that class
          
            - “a dolphin is a mammal living in water”
- we restrict the value of “living in”
 
- Restriction may be by:
						- value constraints (i.e., further restrictions on the range)
								- all values must be from a class
- 
                  at least one value must be from a class
 
- cardinality constraints
- (i.e., how many times the property can be used on an instance?)
								- minimum cardinality
- maximum cardinality
- exact cardinality