Math E-320: Spring 2013

Teaching Math with a Historical Perspective

Mathematics E-320: Sun Graphs

Instructor: Oliver Knill

Office: SciCtr 432

Email: knill@math.harvard.edu

A graph (V,E) is a collection of nodes V and edges E each connecting two nodes. The following figures show a simple type of graphs called "sun graphs". Start with a circular closed loop graph and attach to each of its node a line graph of random length. Thats it. Mathematica draws this graph with an electric embedding notion. That is the nodes are placed so that the electric energy is minimized. This produces beautiful pictures, despite the simplicity. The first picture shows the construction best. It is a graph where we started with a loop of length 20, then added rays of random length between 0 and 20. Click on one of the thumbnails below to see a larger picture.

Please send questions and comments to knill@math.harvard.edu