  Some surviving companions of type Ia supernovae (SNe Ia) from the white-dwarf
+ main-sequence (WD + MS) channel may evolve to hot subdwarfs. In this paper,
we preformed stellar evolution calculations for surviving companions of close
WD + MS systems in the spin-up/spin-down model and the canonical non-rotating
model to map out the initial parameter spaces in the orbital period - secondary
mass plane in which the surviving companions can evolve to hot subdwarfs. Based
on these results, we carried out a series of binary population synthesis
calculation to obtain the Galactic birth rate of the hot subdwarfs from the WD
+ MS channel, which is $2.3-6\times10^{\rm -4}\,{\rm yr}^{\rm -1}$ for the
spin-up/spin-down model and $0.7-3\times10^{\rm -4}\,{\rm yr}^{\rm -1}$ for the
canonical non-rotating model. We also show the distributions of some integral
properties of the hot subdwarfs, e.g. the mass and the space velocity, for
different models. In addition, comparing our results with the observations of
the intermediate helium-rich (iHe-rich) hot subdwarfs, the hot subdwarfs from
the WD + MS channel may explain some observational features of the iHe-rich hot
subdwarfs, especially for those from the spin-up/spin-down model. Although we
expect that the SN Ia channel can only contribute a small fraction of the
iHe-rich hot subdwarf population, some of these may help to explain cases with
unusual kinematics.
