TY - INPR A1 - Tarkhanov, Nikolai Nikolaevich T1 - Unitary solutions of partial differential equations N2 - We give an explicit construction of a fundamental solution for an arbitrary non-degenerate partial differential equation with smooth coefficients. T3 - Preprint - (2005) 09 KW - fundamental solution KW - geometric optics approximation Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-29852 ER -