bio  website  math.ucla.edu/~pak 

location  Los Angeles, CA  
age  
visits  member for  4 years, 8 months 
seen  1 hour ago  
stats  profile views  8,310 
1d

revised 
Pach's “Animals”: What if the genus is positive?
link fixed 
Oct 4 
comment 
(non)existence of the aperiodic monotile
Not exactly. That paper talks only about tilings of the plane with parallel traslates. These are MUCH easier than general tilings. 
Sep 30 
awarded  Explainer 
Aug 15 
awarded  Good Answer 
Aug 8 
comment 
What exact number of domino tilings cannot be realizable?
Let's say you have two integers $m<n$. Can you always find a s.c. region $G$ and a domino $D \subset G$, s.t. $G$ has exactly $n$ tilings, but $GD$ has only $m$? 
Jul 13 
answered  What is known about tiling a rectangle in an irreducible way by smaller rectangles? 
Jun 14 
answered  A Simple Bijective Proof Of Stanley's HookContent Formula for Hook Shapes 
May 6 
awarded  Nice Answer 
Mar 5 
awarded  Enlightened 
Mar 5 
awarded  Nice Answer 
Feb 24 
awarded  Necromancer 
Feb 16 
awarded  Nice Answer 
Feb 16 
awarded  Yearling 
Feb 16 
answered  Conjecture on NPcompleteness of tesselation of Wang Tile up to finite size 
Feb 14 
awarded  Good Answer 
Feb 11 
comment 
How hard is it to determine if a weighted graph can be isometrically embedded in R^3?
Actually, (3) applies to nonconvex triangulated spheres as well. Of course, nothing is impossible, but even for the icosahedron with slightly perturbed edge lengths, the degrees of equations are not very encouraging (between 2^10 and 2^30). 
Feb 10 
answered  How hard is it to determine if a weighted graph can be isometrically embedded in R^3? 
Jan 14 
awarded  Nice Answer 
Jan 14 
revised 
Minimal generating sets of groups
copy 
Jan 14 
answered  Minimal generating sets of groups 