It is in projective geometry. It's not in affine geometry. Get with the (Erlanger) program, Betty.
IEEE arithmetic on reals treats infinity and -infinity (and indefinite) as ordinary numbers (with some special rules.) The proposed Language Independent Arithmetic standard has three zeros too (in some versions), plus zero, ordinary zero, and minus zero. This makes many computations run much more smoothly.
I'd be glad to check it out, Doc. Got a source for me?
Thanks so much for writing!