Possible relativistic generalization of the Feynman approach to quantum mechanics

A relativistic generalization of the Feynman approach to quantum mechanics is discussed. The discussion is carried out in terms of the evolution parameter τ, which does not enter the metric of the fivedimensional space Е_4,1. This scheme may find application at distances of the order of ~ 10^{- 11}cm or times of the order of 10^{-21}sec.