text: unlike many languages it does not have a unique names assumption. Unless specifically stated otherwise, 
  the reasoner can infer that two individuals with different names are actually the same individual. It should 
  be noted however, that if Peggy and Margaret were explicitly stated to be two diﬀerent individuals then 
  the above statements would lead the reasoner to infer that there was an inconsistency in the ontology. We 
  will discuss names more in chapter 7. 
  
  In section 4.16 we will discuss cardinality restrictions on properties. E.g., that the hasWheel property of 
  the Bicycle class has a minimum of 2 (allowing for training wheels) whereas hasWheel for the 
  Unicycle class is defined to be exactly 1. A functional property is equivalent to a property with a 
  cardinality restriction that says it has a maximum of 1 value. The term functional is from mathematics 
  where a function is defined as a relation where each member of the domain has at most one value. For 
  example, the greaterThan relation is not functional since for any number X many (in fact an infinite 
  number) can be greaterThan X but the plusOne relation is functional since for any number X 
  plusOne always results in one unique value. 