B3D-Chapter 9

Irene Klein

Well, this is it. The final chapter of B3D. The last response for this book.

I thought that it was interesting that, although this chapter dealt with non-Euclidean geometry, the actual names of the non-Euclidean geometries were never explicitly stated.

In addition, the pseudosphere struck me. What dimension is it in? Is it a four space projected into three space? Or, is it like a sphere and spherical coordinates?

Next, I really had a difficult time visualizing the real projective plane. I did not notice a picture of it in the book. Was there one?

Finally, I really liked the example with the Mobius Band and the superposed triangle. That really gave me a different perspective on it.