ABSTRACT

We will now take a look at the unusual world of non-Euclidean geometries, speci cally at the hyperbolic geometry.

Recall the ve Euclidean postulates of the planar geometry (see Section 1.1), in particular, the h postulate that states the following:

For every line l and every point P that does not lie on l, there exists a unique line m through P and parallel to l (see Figure 4.1.1).