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8 votes
0 answers
544 views

Maximal set on hypersphere that does not contain pairs of orthogonal vectors

Let R be a region on a hypersphere. Each point A of the hypersphere is associated with a vector pointing to A and with origin at the centre of the hypersphere. So let me identify each point with a ...
Alm's user avatar
  • 1,207
7 votes
0 answers
254 views

Set of unit vectors such that among any three there is an orthogonal pair

I was fascinated by the solutions of Problem 8 of the IMC 2021 contest, which can be summarized as: Theorem 1. Let $v_1,\dotsc,v_N$ be distinct unit vectors in $\mathbb{R}^n$ such that among any three ...
GH from MO's user avatar
  • 105k
5 votes
0 answers
310 views

Biggest (or large) rectangle in a polytope

I need an efficient method to construct a (hyper)rectangle inside a polytope with a lot of dimensions (say $100 < d < 1000$). Ideally I'd want the biggest possible rectangle, but as I don't ...
Elliot Gorokhovsky's user avatar
2 votes
0 answers
233 views

Do you know this formula for the scalar product in barycentric coordinates?

I've found a formula for a scalar product in barycentric coordinates which I think is pretty cool. I hope that it's new. Is it? Suppose that you have points $x_1,\dots,x_n$ sitting in general position ...
Vladimir Zolotov's user avatar