Derivation of quantum theories:symmetries and the exact solution of the   derived system
  Based on the technique of derivation of a theory, presented in our recent paper, we investigate the properties of the derived quantum system. We show that the derived quantum system possesses the (nonanomalous) symmetries of the original one, and prove that the exact Green functions of the derived theory are expressed in terms of the semiclassically approximated Green functions of the original theory. 
M. Khorrami, A. Aghamohammadi and M. Alimohammadi