  In a recent paper Klebanov and Witten (hep-th/9905104) proposed to formulate
the AdS/CFT correspondence principle by taking an "irregular boundary
condition" for a scalar field. In this paper we generalize this idea to the
case of spinor field with interaction. The action functional following from the
choice of irregular boundary conditions and which must be used in the AdS/CFT
correspondence is related to the usual action by a Legendre transform. For the
new theory we found the modified Green's function that must be used for
internal lines in calculating higher order graphs. It is proved that the
considerations are valid to all orders in perturbation theory.
