Geodesic
Two New Approaches to Obtaining Estimates in the Danzer--Gr\"unbaum Problem
Matematičeskie zametki, Tome 87 (2010) no. 4, pp. 519-527.

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We use probabilistic methods to estimate the cardinality of a set $S$ in a Euclidean space such that no three points of $S$ form a right or an obtuse angle. Let $a(n)$ be the cardinality of a maximal subset $S\subset\mathbb R^n$ with this property. We prove that $$ a(n)\ge\frac23\biggl\lfloor\sqrt2\biggl(\frac2{\sqrt3}\biggr)^n\biggr\rfloor. $$
Keywords: Euclidean space, angle, set of points, Danzer–Grünbaum problem, Erdős–Füredi method. 
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L. V. Buchok. Two New Approaches to Obtaining Estimates in the Danzer--Gr\"unbaum Problem. Matematičeskie zametki, Tome 87 (2010) no. 4, pp. 519-527. http://geodesic.mathdoc.fr/item/MZM_2010_87_4_a4/

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