  A field-theoretical description of the behavior of disordered, elastically
isotropic, compressible systems characterized by two order parameters at the
bicritical and tetracritical points is presented. The description is performed
in the two-loop approximation in three dimensions . The renormalization group
equations are analyzed, and the fixed points corresponding to different types
of multicritical behavior are determined. It is shown that the effect of
elastic deformations causes a change in the regime of the tetracritical
behavior of disordered systems because of the interaction of the order
parameters through the deformation field.
