It's a little more basic than that. I'm no graph theory expert and reading
such stuff gives me a headache, but I do understand that abstraction
(summarization or aggregation) of routing information is only possible if the
identifiers that are used for numbering network elements (the
"addresses") are assigned in a manner that is isomporphic to
the network topology. TLi started writing a good paper which
described this in terms of sets and subsets; unfortunately, I
don't think it ever saw the light of day).