(36) by $-\frac {\partial S}{\partial t}$ and using (35) to replace the second term in (36) we get from (34) $$\frac {\partial S}{\partial t}=-\frac {1}{2a^3}(\frac {\partial S}{\partial
\phi})^2
-a^3 V(\phi)+a(P_a^0)'+3a^3 V_0.$$ When $V(\phi)\approx V_0$, the Hamiltonian constraint is $$-\frac {(P_a^0)^2}{2Ma} - \frac {Mka}{2} + a^3 V_0=0$$ Using (38) in (35) we get $$(P_a^0)'= Mk - 4a^2 V_0$$ In the region, $4a^2\frac{V_0}{M}>> 1$, (we now consider $k=+1$) we have $$a(P_a^0)'=-4a^3V_0$$ Putting this value in (37), we finally get $$\frac {\partial S}{\partial t}= -\frac {1}{2a^3}(\frac {\partial S}{\partial \phi})^2
-a^3(V(\phi)+V_0).$$ It is now straightforward to quantize (41) identifying $P_t={{\partial S}\over {\partial t}}$ and $P_\phi=\frac {\partial S}{\partial \phi}$. Upon quantization we get $$i \frac {\partial \Psi(a,\,\phi)}{\partial t}=[-{\frac {1}{2a^3}}
\frac {\partial^2}{\partial\phi^2} +a^3(V(\phi)+V_0)]\Psi(a,\,\phi).$$ In (42), $\Psi$ refers to the wavefunction of the universe, in which $a(t)$ is given by the solution of classical constraint equation. In this sense, apart from the extra term $V_0$ (that one does not have through ‘time’ after quantization) (42) takes the equivalent role as does the Wheeler-DeWitt equation. We will show this in the next section. In obtaining (42) we have nowhere used the Wheeler-DeWitt equation and the corresponding WKB ansatz for $\Psi$. Equation (42) is our Schroedinger-Wheeler-DeWitt equation. We need 