Problem of the Week
Hilton Memorial Lecture
The flow of current in an electrical network behaves according to Kirchhoff's Laws. I will discuss analogues of these Laws that hold for arbitrary directed graphs by analyzing a special class of spanning (directed) subgraphs for which a `transpedance' can then be associated to each directed edge. These transpedances satisfy Kirchhoff's Laws that can be extend to graphs to illustrate Kirchhoff's Laws for electrical networks. Time permitting, I will also discuss a (surprising?) computational method for calculating transpedances.