  In minimally coupled scalar field theories with a potential of the slow-roll
type, we give a detailed description of the complex $O(4)$-symmetric solutions
to Einstein's equations on the four-ball which contribute to the no-boundary
amplitude $\Psi_\textsf{NB}(b,\chi)$ for a closed universe to contain a round
three-sphere spatial slice of size $b$ covered homogeneously with the scalar
field at value $\chi$. Our derivation demonstrates a result anticipated by
Hartle, Hawking and Hertog in Phys. Rev. D 77 (2008) 123537 [arXiv:0803.1663],
sharpens Vilenkin's result in Phys. Rev. D 37 (1988) 888 in the classical
regime of the minisuperspace and makes use of a complexified slow-roll
approximation. Our technique applies to both the Hartle-Hawking and Vilenkin
wave functions, which both predict a family of inflationary universes but
weight each member exponentially differently in the semiclassical
approximation.
