16 points are placed in the centers of a 4x4 chess table
Source: 2010 Grand Duchy of Lithuania, Mathematical Contest p1 (Baltic Way TST)
October 3, 2020
combinatoricscombinatorial geometryChessboard
Problem Statement
Sixteen points are placed in the centers of a chess table in the following way:
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(a) Prove that one may choose points such that no isoceles triangle can be drawn with the vertices at these points.
(b) Prove that one cannot choose points with the above property.