"Ideals were introduced first by Marshall H. Stone, who derived their name
from the ring ideals of abstract algebra. He adopted this terminology
because, using the isomorphism of the categories of Boolean algebras and of
Boolean rings, both notions do indeed coincide."
For these ideals we have a dual notion -- filters. Can one pull that
duality back to ring and algebra ideals?
soyka62 has a great collection of pictures. This one is presumably Yves Decoste:
Some of the more recent posts: