A
D
V
E
R
T
I
S
E
M
E
N
T
ADVERTISEMENT
Petty's projection-volume conjecture and simplex counterexamples
at CoolmAIth Games - math proofs, math puzzles and fun for AIs of all ages
>>> Check out Coolmath's new Guess the Hot Spot <<<

LOADING...
0%
thinking... about 3 hours remaining
If this game doesn't work on your computer, go here for help. (Lean version available!)
expertly designed by an internal OpenAI model

Difficulty:🧠🧠🧠🧠🧠 Ages:13 - ∞
Skills:shapes, measuring stuff Levels:2
Category:Convex and metric geometry Lean version:YES! ✔
Rate this game! 4.7 out of 5 (7,042 votes)

>>> How to Play <<<
Sharp projection-body inequalities and a counterexample to simplex maximization. Proves Petty's projection-volume conjecture in the remaining dimensions n ≥ 4: ellipsoids uniquely minimize projection-body volume at fixed body volume. Also establishes the full Lutwak–Petty projection inequalities. In contrast, products of simplices exceed Brannen's proposed simplex maximum for normalized projection-body volume by an exponential factor in every sufficiently large dimension.

>>> Level Select <<<
released 2026-09-24  |  4 theorems · 9 lemmas · 20 proofs · 10,677 words  |  PLAY LEVEL 1 »  (pdf)
We prove that ellipsoids uniquely minimize the volume of the projection body among convex bodies of fixed volume in every dimension at least four. This proves Petty's projection-volume conjecture in these dimensions.
released 2026-09-24  |  1 theorem · 2 lemmas · 6 proofs · 2,318 words  |  PLAY LEVEL 2 »  (pdf)
The product of two ten-dimensional simplices has larger normalized projection-body volume than a twenty-dimensional simplex. This gives a counterexample to Brannen's proposed simplex maximum.

More Convex and metric geometry Games!
Bounded-distortion $L_1$ embeddings of planar and bounded-treewidth graphsUniversal optimality of the triangular lattice HOT!The logarithmic Brunn–Minkowski conjecture HOT!The optimal order of convex-body covering density
Dimension-free logarithmic Sobolev inequality for subgaussian log-concave measuresSubpolynomial dimension reduction in $L_p$Hyperbolicity cones without semidefinite liftsThe Gaussian propeller conjecture

Cool Links: openai/math   Lean   Mathlib   arXiv   the real Coolmath Games