A more interesting approach
is based on the realization that this domain is relational.It has objects that are linked to each
other.And the links are very
meaningful in and of themselves.For
example, a student webpage is very likely to point to his advisor’s
page.But faculty rarely link to each
other, neither do courses and researh projects.
Note that we can’t have an
edge directly between categories of the pages – this will cause cycles in the
However we can represent
these trends by asserting that the existence of a link depends on the
category of the two pages pointing to it. This allows us to use, for example,
a webpage that we are fairly sure is a student page to give evidence about
the fact that a page it points to is a faculty webpage.In fact, they can both give evidence about
each other, giving rise to a form of “collective classification”.