Abstrakt
Let d and k be integers with 1 0 is an arbitrarily small constant. This nearly settles a problem mentioned in the book of Brass, Moser, and Pach.
We also find tight bounds for the minimum number of k-dimensional affine subspaces needed to cover the intersection of Lambda with K. We use these new results to improve the best known lower bound for the maximum number of point-hyperplane incidences by Brass and Knauer.
For d > =3 and epsilon in (0,1), we show that there is an integer r=r(d,epsilon) such that for all positive integers n, m the following statement is true. There is a set of n points in R^d and an arrangement of m hyperplanes in R^d with no K_(r,r) in their incidence graph and with at least Omega((mn)^(1-(2d+3)/((d+2)(d+3)) - epsilon)) incidences if d is odd and Omega((mn)^(1-(2d^2+d-2)/((d+2)(d^2+2d-2)) - epsilon)) incidences if d is even.