3,006 reputation
932
bio website mathpuzzle.com
location Champaign, IL
age 50
visits member for 2 years, 10 months
seen 13 hours ago

I run the site mathpuzzle, and used to be the main advisor for the TV show Numb3rs. I've contributed extensively to MathWorld. Before that, I wrote the Math Games columns for the MAA. I am now the chief editor for the Wolfram Demonstrations Project. Of my own Demonstrations there, some of my favorites are: - Mrs. Perkins's Quilts - Tightly Packed Squares - Social Golfer Problem - The Circles Of Descartes - Triangle Calculator


Mar
20
answered tetrahedron height
Mar
20
revised Prove that Petersen's graph is non-planar using Euler's formula
edited body
Mar
20
revised Prove that Petersen's graph is non-planar using Euler's formula
deleted 137 characters in body
Mar
20
answered Prove that Petersen's graph is non-planar using Euler's formula
Mar
19
answered What are the simple Heesch-2 polyforms?
Feb
17
awarded  Revival
Feb
17
revised Is there any hope to disprove goldbach's conjecture?
deleted 4 characters in body
Feb
17
answered Is there any hope to disprove goldbach's conjecture?
Jan
26
reviewed Approve suggested edit on Convergence in $L^\infty$ norm and continuous function
Jan
24
answered Making the water gallon brainteaser rigorous
Jan
24
reviewed Approve suggested edit on Proving that this is not a group.
Jan
23
reviewed Approve suggested edit on Find $\sum_{r=0}^{2n}\frac{r}{r+2}\binom{2n}r\;.$
Jan
23
asked What are the simple Heesch-2 polyforms?
Jan
23
comment How to prove that a particular polyiamond tiles the Euclidean plane?
With the V shape, lay down one. To fill the hole, the next piece is forced. To fill that hole, the next move is forced. A few more forced moves gives unfillable holes. Generally, the non-tilers cannot surround themselves, the Heesch problem, but there are many non-tilers that are Heesch-2.
Jan
23
comment How to prove that a particular polyiamond tiles the Euclidean plane?
Octiamond tilings -- When a repeated tiling with translation is found, you've divided the plane into identical cells with identical orientation. Each cell will have some number of of polyforms.
Jan
22
answered How to prove that a particular polyiamond tiles the Euclidean plane?
Jan
22
reviewed Approve suggested edit on Space of Continuous mappings to metric spaces
Jan
22
reviewed Approve suggested edit on Equality of $L_2$ norm on $[0, \infty)$
Jan
21
comment Comparison of almost planar graphs
Crossing number is currently easier to calculate, because the program is written. I don't know of an existing "is this graph toroidal?" checker, but I'd love to run it on a bunch of graphs if someone has it.
Jan
20
answered Comparison of almost planar graphs