Three-band model of high-T-c superconductivity

We reduce the three-band model of planar CuO2 to a single-band of composite fermions. We obtain hopping parameters t(eff)(R-ij), repulsive potentials U-eff and V(R-ij), and the superexchange interactions J(R-ij) necessary for both antiferromagnetism and superconductivity. The ratios of these quantit ies are determined by a unique parameter x approximate to 3.9t(pd)/U-dd Fai ring symmetry crosses over from "extended s" to "d" as function of carrier concentration. We show why only the latter survives near the antiferromagne tic point. [S0163-1829(99)00110-1].