  The Einstein field equations for any spherically symmetric metric and a
geodesic perfect fluid source are cast in a canonical simple form, both for
Lorentzian metrics and for instantons. Both kinds of metrics are explicitly
written for the Lema{\^{\i}}tre-Tolman-Bondi family and for a general
$\Lambda$-Friedmann-Lema{\^{\i}}tre-Robertson-Walker universe. In the latter
case (including of course the instanton version) we study whether the
probability of quantum creation of our Universe vanishes or not. It is found,
in accordance with previous results, that only the closed model can have a
nonzero probability for quantum creation. To obtain this result, we resort to
general assumptions, which are satisfied in the particular creation case
considered by Vilenkin. On the other hand, Fomin and Tryon suggested that the
energy of a quantically creatable universe should vanish. This is in accordance
with the above result in which only the closed $\Lambda$FLRW model is
quantically creatable while the open and flat models are not. That is so since
it can be seen that this closed model has vanishing energy while the open model
and the limiting flat case (suitably perturbed) have both infinite energy.
