  We present V- and I-equivalent HST/WFPC2 stellar photometry of an area in the
Large Magellanic Cloud (LMC), located on the western edge of the bar of the
galaxy, which accounts for the general background field of its inner disk. The
WFPC2 observations reach magnitudes as faint as V=25 mag, and the large sample
of more than 80,000 stars allows us to determine in detail the Present-Day Mass
Function (PDMF) of the detected main-sequence stars, which is identical to the
Initial Mass Function (IMF) for masses M <~ 1 M_solar. The low-mass
main-sequence mass function of the LMC field is found not to have a uniform
slope throughout the observed mass range, i.e. the slope does not follow a
single power law. This slope changes at about 1 M_solar to become more shallow
for stars with smaller masses down to the lowest observed mass of ~ 0.7
M_solar, giving clear indications of flattening for even smaller masses. We
verified statistically that for stars with M <~ 1 M_solar the IMF has a slope
Gamma around -2, with an indicative slope Gamma =~ -1.4 for 0.7 <~ M/M_solar <~
0.9, while for more massive stars the main-sequence mass function becomes much
steeper with Gamma =~ -5. The main-sequence luminosity function (LF) of the
observed field is in very good agreement with the Galactic LF as it was
previously found. Taking into account several assumptions concerning
evolutionary effects, which should have changed through time the stellar
content of the observed field, we reconstruct qualitatively its IMF for the
whole observed mass range (0.7 <~ M/M_solar <~ 2.3) and we find that the number
of observed evolved stars is not large enough to have affected significantly
the form of the IMF, which thus is found almost identical to the observed PDMF.
