# Talk:Four Color Theorem

## Contents

### Abram 7/9

Nice page.

The one thing that needs to be changed is where you talk about a "three-dimensional sphere" in the more mathematical section. A lot of mathematicians think of this as a 2-dimensional sphere, because it is a 2-d surface that happens to live in 3-d space. You may want to just say "sphere" instead, as this meaning is unambiguous.

Also, as the page stands currently, 90% of people reading the page will assume that the connection between a planar graph and a map is that vertices of the graph correspond to vertices on the map, and "regions" in the planar graph correspond to territories on the map. Even though you specifically explain that territories are represented by vertices, people won't recognize that you've kind of switched points with 2-dimensional regions if you don't make a big stink about the fact that you've pulled this switcheroo on them.

Of course, people can still get most of what you are saying, blissfully unaware that they are missing a key detail, so you could just let this go. But I thought you oughta know. Maybe you could show a picture of a very simple map with a corresponding planar graph that obviously looks different?

### Anna 7/8

Can you have some references and links at the bottom? One in the paragraph that mentions history (so that people can read more about it right there) would also be good.

### Brendan 7/8

Ok, I moved a chunk of the more mathematical explanation into the basic description.

### Anna 7/7

I agree that it is more mathematical. My only concern is that people without a strong math background won't feel comfortable clicking to unhide it. So... I'd either slightly retitle the section, or just completely unhide it.

### Brendan 7/7

I mentioned the history briefly, and I think I'll leave it at that for an image page (there is, of course, plenty of material elsewhere online if my mention of the history catches the reader's interest).

I agree that the entire page could go into the basic description section, but I felt it fit better into the site's template to have separate sections. The more mathematical description is more mathematical, even though it can be understood without college or even a high school math background.

### Anna 7/6

I linked to the Torus page for you.

I also think it might be nice to have a short paragraph about the history of the theorem somewhere, just because it's so rich.

### Anna 6/26

I actually feel like the whole page could easily go into the "basic description" with the exception of the stuff about the torus. It doesn't really require significant background knowledge.

If you want to add a more mathematical section, a bit about the five color theorem, which is easy to prove, might be interesting. Otherwise, I'd just fiddle around with the section headings.

I really like content of the page, and I think it's really well written.

Can that first bit of text be a complete sentence? (sorry to be the grammar police)

-Anna 6/9

### Harrison 5/16

Could use a description of the algorithm used to describe the model.