  Using the method of searching for arbitrary shaped voids in the distribution
of volume-limited samples of galaxies from the DR5 SDSS survey, we have
identified voids and investigated their characteristics and the change in these
characteristics with decreasing Mlim - the upper limit on the absolute
magnitude of the galaxies involved in the construction of voids. The total
volume of the 50 largest voids increases with decreasing Mlim with a break near
Mr* = -20.44 for SDSS galaxies. The mean density contrast in voids increases
with decreasing Mlim also with a weak break near M*. The exponent of the
dependence of the volume of a void on its rank increases significantly with
decreasing Mlim starting from Mlim ~ -20.4 in the characteristic range of
volumes, which reflects the tendency for greater clustering of brighter
galaxies. The galaxies mostly tend to concentrate toward the void boundaries
and to avoid the central void regions. The axial ratios of the ellipsoids
equivalent to the voids are, on average, retained with changing Mlim and
correspond to elongated and nonoblate void shapes, but some of the voids can
change their shape significantly. The void centers show correlations reflecting
the correlations of the galaxy distribution on scales (35-70)/h Mpc. The galaxy
distribution in the identified voids is nonrandom - groups and filaments can be
identified. We have compared the properties of the galaxies in voids and
galaxies in structures identified using the minimum spanning tree. A noticeable
difference is observed in the mean color indices and star formation rates per
unit stellar mass of the galaxies in dense regions (structures) - as expected,
the galaxies in voids are, on average, bluer and have higher log(SFR/M_star).
These tendencies become stronger toward the central void regions.
