@christianp

I like the three color addition! Is this a common property of projective planes (maybe it's trivial?...I'm not used to thinking about the points as repeated like this! 🙂 ) or one of the named adjectives (Desarguesian, etc.)?

I realise now that the way I have been saying this fact is very ambiguous (I can make it make sense with tone of voice and hand gestures).

I mean to say there is exactly one number that is the successor of a square and whose successor is a cube, or to put it another way, there is exactly one solution to y³-x²=2 with x,y integers.

3/n

The slope number of a graph G is the minimum number of distinct gradients of the edges in a straight line drawing of G.

An open problem that is very nice in my opinion: When Δ(G)≤3 the slope number of G is at most 4. For any k there is a graph G with Δ(G)=5 and slope number >k. But what about Δ(G)=4?

Not really my area at all but I like questions like this: where's the boundary?

Mathematician, computer scientist, bassist, knitter?

Joined Jan 2018