It seems that you are defending a wrong point of
view (if we are discussing the standard definitions at least). Say Minkowski space-time is
homogenious and isotropic and posesses the corresponding group of transfomations. This fact
is irrelevant to the coordinate system you use.
Even in rotating coordinate system the metric
will have a special form respecting these symmetries. On the other hand clumps of matter
do produce inhomogenities. Look at textbooks for
definitions (Theory of Fields, Gravitation, and
so on...). |