stekas@hou2g.UUCP (J.STEKAS) (03/09/84)
> In fact, the >plane and the sphere are topologically equivalent (the plane is a sphere >if infinite radius) ... This statement has been made so frequently that I think it's time someone took exception. A plane and sphere are NOT topologically equivalent, a sphere has an additional point. That's why plane like coordinate systems mapped to a sphere always have a point where the coordinates are undefined. In any case, spherical and planar maps can both be colored with the same number of colors. Jim