  Ground state wave function of two-dimensional t-J model is found at doping
close to half filling. It is shown that the condensation of Cooper pairs
(superconducting pairing of mobile holes) and the condensation of spin-waves
into spin-liquid state are closely connected. The effective spectrum of $S=1$
excitations, spin-wave gap pseudo-gap $\Delta_M$, magnetic correlation length
$\xi_M$, and static magnetic formfactor $S_M(\bf q)$ are calculated.
