  We present an asymptotically exact solution of a local copper-oxide model
abstracted from the multi-band models. The phase diagram is obtained through
the renormalization-group analysis of the partition function. In the strong
coupling regime, we find an exactly solved line, which crosses the quantum
critical point of the mixed valence regime separating two different
Fermi-liquid (FL) phases. At this critical point, a many-particle resonance is
formed near the chemical potential, and a marginal-FL spectrum can be derived
for the spin and charge susceptibilities.
