We characterize the smallest (best) barrier parameter of self-concorda
nt barriers for homogeneous convex cones. In particular, we prove that
this parameter is the same as the rank of the cone which is the numbe
r of steps in a recursive construction of the cone (Siegel domain cons
truction). We also provide lower bounds on the barrier parameter in te
rms of the Caratheodory number of the cone. The bounds are tight for h
omogeneous self-dual cones. (C) 1998 The Mathematical Programming Soci
ety. Inc, Published by Elsevier Science B.V.