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