Bounds on selection networks

We investigate the complexity of network selection by measuring it in terms of U(t,N), the minimum number of comparators needed, and T(t,N), the minimum delay time possible, for networks selecting the smallest t elements from a set of N inputs. New bounds on U(t,N) and T(t,N) are presented. In particular, U(3,N) is determined to within a constant of 2, and asymptotic formulae for U(t,N) and T(t,N) are given for fixed t.