  A definition is given, in the framework of stochastic quantization, for the
dynamics of a system composed of classical and quantum degrees of freedom
mutually interacting. It is found that the theory breaks reflection positivity,
and hence it is unphysical. The Feynman rules for the Euclidean vacuum
expectation values are derived and the perturbative renormalizability of the
theory is analyzed. Contrary to the naive expectation, the semiquantized theory
turns out to be less renormalizable, in general, than the corresponding
completely quantized theory.
