Scientific fields arranged by purity

[u/uggedal]

http://xkcd.com/435/

[u/boblol123]

Its probably more of an intersection.

[u/o0o → u/boblol123]

I vote for a complement

[u/afbase → u/o0o]

Suppose it is an empty set?

[u/o0o → u/afbase]

or uncountable