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.
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.