Jean-Marc Valin wrote: > > > So, what are nodes a subclass of? > > The Node class doesn't have any parent, though it might inherit from Object if > we need to (probably). ...and Network inherits from Node. Maybe I should say 'subset' rather than 'subclass', so that I'm not confusing OO terminology with ordinary logic. This is what I'm trying to saying in logical terms: The Overflow way: 'Documents' contain networks Networks are of types subnet and iterator Networks contain nodes and links But can't we say... Nodes contain links and networks Networks are of types subnet and iterator Networks contain nodes Nodes contain links and networks ... Jeff -- +----------------------------------+ | J.W. Bizzaro | | | | http://bioinformatics.org/~jeff/ | | | | BIOINFORMATICS.ORG | | The Open Lab | | | | http://bioinformatics.org/ | +----------------------------------+