# Thread: Dual graph

1. ## Dual graph

Draw the dual graph for the following graph.

ok my answer is

somethings telling me I stuffed up....

2. ## Re: Dual graph

Originally Posted by bee77
Draw the dual graph for the following graph.

ok my answer is

3. ## Re: Dual graph

Call your first graph G and the dual G*.

G has 6 vertices; this means there will be 6 faces in G*.

G has 4 faces; this means there will be 4 vertices in G*.

G has 8 edges; this means there will be 8 edges in G*.

4. ## Re: Dual graph

Need some practice with these thanks all

5. ## Re: Dual graph

Originally Posted by bee77
Need some practice with these thanks all
You also need to tell us what definition of duel your course is using.
I am sitting here looking at a self of some eight textbooks commonly used in North America. Each of those define the duel of a simple planar graph as the vertex set is the set of faces and an edge means the faces share a boundary edge.
I have discovered that a somewhat different definition in use in the European sphere of influence. You seem to be using that definition.

6. ## Re: Dual graph

Hey Plato here's the snipping from the lecture slides we use .

I'm not to sure to be honest as our class has just been introduced to these so I just drew what I thought ...