Tomaž Pisanski: On the maximum number of independent elements in configurations of points and lines

We show that the upper bound for the maximum number of independent elements of a (v_r) configuration is given by ⌊2v/(r+1)⌋ and that this bound is attained for all integer values of r by geometric configurations of points and lines in the Euclidean plane. This disproves a conjecture by Branko Grünbaum.