I tried to find a proof online one way or the other, but there seems to be no concrete consensus. It's possible that whether or not elliptic geometry is a subse

I tried to find a proof online one way or the other, but there seems to be no concrete consensus. It's possible that whether or not elliptic geometry is a subset of absolute geometry is a consequence of the formulation of the axioms - since you can modify any axiom involving the existence of parallel lines using something like "If parallel lines exist, then...". Certainly the way I learned it was that the parallel postulate is the only axiom which distinguishes the elliptic, Euclidean, and hyperbolic geometries.