Let Y be a real analytic set.
The subset of Y consisting of all points where the local dimension of Y is maximal is
called the main part of Y . A subset Y ′ of a real analytic manifold N is
called a main semi-analytic set if Y ′ is the main part of some analytic set
in a neighborhood of each point of N. In this paper it is shown that any
proper C∞ mapping between analytic manifolds can be approximated by an
analytic mapping in the Whitney topology so that the critical value set
is a main semi-analytic set. An analogue holds true for the algebraic case
too.