◀ ▲ ▶Branches / Graphtheory / Lemma: Handshaking Lemma for Planar Graphs
Lemma: Handshaking Lemma for Planar Graphs
Let $G(V,E)$ be a biconnected planar graph with a given planar drawing $\mathcal D.$ Then the sum of face degrees in the drawing is equal to twice the number of edges, formally
$$\sum_{f\in \mathcal D}\deg (f)=2\cdotE.$$
Table of Contents
Proofs: 1
Mentioned in:
Proofs: 1 2
Thank you to the contributors under CC BYSA 4.0!
 Github:

References
Bibliography
 Aldous Joan M., Wilson Robin J.: "Graphs and Applications  An Introductory Approach", Springer, 2000