  We have constructed a Main galaxy subsample with redshifts in the range
0.08<=z<=0.12 from SDSS Data Release 3 (SDSS DR3), and refer to this subsample
as "MGSU"(It contains 67777 galaxies). By cluster analysis, two isolated Main
galaxy samples are extracted from this subsample. It turns out that two
isolated Main galaxy samples identified at different radii have the same
properties. Additionally, we also find that early-type galaxies in isolated
Main galaxy samples are fewer than that in close double galaxy sample.
