MathDB

Show that the edges of a strongly connected bipolar graph can be oriented in such a way that for any edge

e

there is a simple directed path from pole

p

to pole

q

containing

e

. (A strongly connected bipolar graph is a finite connected graph with two special vertices

p

and

q

having the property that there are no points x,y,x \not \equal{} y, such that all paths from

x

p

as well as all paths from

x

q

contain

y

.) A. Adam

Problem Statement