  We consider a Kondo impurity coupled to a fermionic host with a power-law
density of states near the Fermi level, rho(epsilon) ~ |epsilon|^r, with
exponent r<0. Using both perturbative renormalization group (poor man's
scaling) and numerical renormalization group methods, we analyze the phase
diagram of this model for ferromagnetic and antiferromagnetic Kondo coupling.
Both sectors display non-trivial behavior with several stable phases separated
by second-order transitions. In particular, on the ferromagnetic side there is
a stable intermediate-coupling fixed point with universal properties
corresponding to a fractional ground-state spin.
