  The contour argument was introduced by Peierls for two dimensional Ising
model. Peierls benefited from the particular symmetries of the Ising model. For
non-symmetric models the argument was developed by Pirogov and Sinai. It is
very general and rather difficult. Intuitively clear that the Peierls argument
does work for any symmetric model. But contours defined in Pirogov-Sinai theory
do not work if one wants to use Peierls argument for more general symmetric
models. We give a new definition of contour which allows relatively easier
prove the main result of the Pirogov-Sinai theory for symmetric models. Namely,
our contours allow us to apply the classical Peierls argument (with contour
removal operation).
