Homework Help: Help me with a proof

1. Apr 7, 2005

SpatialVacancy

Help me with a proof!!!

Suppose that $$G$$ is a graph with $$v$$ vertices and $$e$$ edges and that the degree of each vertex is at least $$d_{min}$$ and at most $$d_{max}$$. Show that:

$$\dfrac{1}{2}d_{min}\ \cdot\ v \ \leq \ e \ \leq \ \dfrac{1}{2}d_{max}\ \cdot\ v$$

I don't have an idea of where to start on this problem. Thank you for your help!

Last edited: Apr 7, 2005
2. Apr 7, 2005

HallsofIvy

Every edge connects 2 vertices. Suppose every edge had degree exactly dmin. How many edges would there be?