Percolation Theory of the Pseudogap Phase

A concept of the pseudogap state in high-$T_c $ layered cuprates on the basis of percolation theory is proposed. Contrary to the self-consistent BCS critical temperature, which defines $T^{\ast}$ - the upper boundary of the psesudogap state, the real critical temperature, $T_c$, is defined, as the percolation threshold, where the infinite cluster appears. This permits to obtain the exact formula for $T_c$, as function of doping and understand its ``dome-like'' shape.