同樣上次那個印度朋友(Syed Imam, chaogold好像跟他更熟)給我的
Let k be a arbitrary real numbers. Prove that the following statement is
true for sufficiently large integer n:
Let a_1, a_2, ..., a_n be n points lying in a circle of radius kn. There
are two integers 1<=i<j<=n such that the distance of a_i and a_j are smaller
than sqrt(j-i).