Problem

Source: Mathcenter Contest / Oly - Thai Forum 2008 R3 p8 https://artofproblemsolving.com/community/c3196914_mathcenter_contest

Tags: geometry, combinatorics, combinatorial geometry



Prove that there are different points $A_0 \,\, ,A_1 \,\, , \cdots A_{2550}$ on the $XY$ plane corresponding to the following properties simultaneously. (i) Any three points are not on the same line. (ii) If $ d(A_i,A_j)$ represents the distance between $A_i\,\, , A_j $ then $$ \sum_{0 \leq i < j \leq 2550}\{d(A_i,A_j)\} < 10^{-2008}$$Note : $ \{x \}$ represents the decimal part of x e.g. $ \{ 3.16\} = 0.16$. (passer-by)