  Inflation with a scalar-field potential of the form \lambda (\phi^2-v^2)^2
can be described in terms of a parametrical attractor with critical points,
whose driftage depends on the control value of the slowly changing Hubble rate.
The method allows us to easily obtain theoretical expressions for fluctuations
of inhomogeneity in both the cosmic microwave background and distribution of
matter. We find the region for admissible values of potential parameters,
wherein theoretical predictions are consistent with experimental results within
the limits of measurement uncertainties.
