Feynman's formula in phase space for systems of pseudodifferential equations with analytic symbols (Q1316845)

We consider the class of systems of second-order equations with unbounded pseudodifferential operators, including systems of differential equations with increasing coefficients. This class contains, in particular, the Dirac equation, as well as the Schrödinger equation for an anharmonic oscillator. In the present article the existence of a local solution is proved for this class of systems and a representation of the solution in the form of a Feynman path integral is presented.