> David R Tribble wrote: > > > (It appears you may be confusing abstract trees > with > > heirarchical > > file systems, which share many of the properties > of > > trees but > > which are not true mathematical trees, but > graphs.) > > You know, here we might see a clash of disciplines. > > In computational theory, a Graph is a subset of a > Tree, i.e. the other way round. > > Indeed, each time you do work on a Graph, what you > start from is your "starting node" (you have to peek > one), so that in our treatment (and I mean the actual > algorithms) Graph Theory is a specialization of Tree > Theory. > > The arbitrariness, or rather the contingency, of your > choice, is what makes a Graph a weak form of Tree.
To complement that, I would also point out that even in treating graphs, you need your dummies.