On Isosceles Sets in the 4‐Dimensional Euclidean Space
Hiroaki Kido · International Journal of Combinatorics · 2010
A subset X in the k‐dimensional Euclidean space ℝk that contains n points (elements) is called an n‐point isosceles set if every triplet of points selected from them forms an isosceles triangle. In this paper, we show that there exist exactly two 11‐point isosceles sets in ℝ4 up to isomorphisms and that the maximum cardinality of isosceles sets in ℝ4 is 11.