The Graph Visualization Problem (4/6): Planar Graphs | Visualization of Graphs - Lecture 1

Visualization of Graphs
Lecture 1: The Graph Visualization Problem
Part IV: Planarity
Philipp Kindermann

[xieyuheng]

At 8:56, When doing a double counting proof,
you should be explicit about what is been counted.
Otherwise a slow minded student (like me) will be confused.
In this case, the number of incidence relations (let it be i) between edge and face are counted.
3f <= i <= 2m

[raksinhaful]

There is a typo at 6:16 => 1-0+n=n+1

[xieyuheng]

9:32 a typo. It should be:
6 <= 3c + 3 = 3f - 3m + 3n
Instead of:
6 <= 3c + 3 <= 3f - 3m + 3n