Directionality in Weird Spaces

• Euclid and not: Riemann, Lobachevsky*, Bolyai, Minkowsky

Metric spaces and graphs

Flavoring a graph with gravity and magnetism

• Some graphs have it (and some don't)

• Sometimes it's not easy to tell

* Ulam, Kuratowski, Mazurkiewicz,Sierpinski, Voronoi, Markov, Chebyshev, Brashman, Lobachevsky