  We consider a RG flow in a general su(2) coset model perturbed by the least
relevant field. The perturbing field as well as some particular fields of
dimension close to one are constructed recursively in terms of lower level
fields. Using this construction we obtain the structure constants and the
four-point correlation functions in the leading order. This allows us to
compute the mixing coefficients among the fields in the UV and the IR theory.
It turns out that they are in agreement with those found recently using the
domain wall construction up to this order.
