  The galaxy cluster power spectrum and mass/temperature functions are
currently the most precise observational tools for constraining the theory of
the formation of large scale structure (LSS) in the Universe. Complementing
these tests by the observational data at larger (cosmic microwave backgroud
anisortopy (CMBA)) and smaller (distribution of $Ly_\alpha$ clouds) scales
opens the way to a straightforward determination of the cosmological parameters
in simplest dark matter (DM) models. We argue that such a 'minimal data set' is
free from systematic effects and can indicate quite precisely the parameters of
spatially flat mixed DM model with a positive cosmological constant and no
cosmic gravitational waves.
