SubtypeRelationship

Last edit September 8, 2006
The inheritance hierarchy (tree in case of SingleInheritance, DirectedAcyclicGraph in case of MultipleInheritance) of types can be represented mathematically by the PartialOrder induced by the subtype-of relation between them.

Example:

   .O.
 .A. .I
 B .C.
   D E
Implies the following relationships (as a matrix):

   OAIBCDE
 O 
 A <
 I <
 B  <
 C  <<
 D     <
 E     <
with the TransitiveHull of subtype-of shown:

   OAIBCDE
 O 
 A <
 I <
 B <<
 C <<<
 D <<< <
 E <<< <
See PartialOrder. (Strict rather than weak partial order used here, but it doesn't really matter.)