### Blog Stats

- 16,354 hits

### Last visits

- 3-edge coloring 4 4 color theorem 4ct Alfred Bray Kempe algorithm Brendan McKay Cahit spiral chains color coloring coloring maps colour cubic graphs different docker edge embedding Euler four Four color four color music four color problem four colors suffice four color theorem Francis Guthrie Fullerene graph graph coloring Graph isomorphism graphs representations Graph theory Gunnar Brinkmann Hamilton homeomorphic impasse isomorphic graphs Java Kempe Kempe chain Kenneth Appel map new features oeis pencil and paper plantri problem proof proper colorings sage sagemath tait Tait coloring theorem tutte Wolfgang Haken
### Blogroll

### Comments

### Meta

# Tag Archives: Graph isomorphism

## Four color theorem: simplified maps and fullerenes

Analyzing all 3-regular graphs that have only faces with 5 edges or more (simplified), I empirically found (using a computer program) that many hypothetically possible graphs, that by Euler’s identity may exist (), do not actually exist. Using a VF2 algorithm to filter out … Continue reading