In article ,
Baz wrote:

[ Venn diagrams ]

It's a bad description, anyway. They are the overlapping circles
(or other shapes) that are often used to illustrate set membership.
The area in circle A but not in B represents the elements that
have propert A but not property B, and the area in the overlap
represents the ones that have both properties. And so on.

A bit like a Vector, a mathematical model to prove or disprove a theory?

Yes and no. They are used to demonstrate properties, rather than
prove them. They are more like graphs (in the school sense).


Regards,
Nick Maclaren.