
Re: Euclids postulates and nonEuclidean geometry
Posted:
Mar 8, 2006 3:07 PM


Hi there, I think the other reason to focus on negations of the fifth postulate, instead of the first, is that without the first postulate we wouldn't call what we're doing "geometry" any more.
Even WILDLY different geometries, like finite geometries, discrete geometries, projective geometries, or what have you, all maintain that through any two points there is a (not necessarily unique?) line.
Joshua Zucker

