Let u(x, x')dx' be an arbitrary microlocal operator. We define the symbol function û(x, ξ of u(x, x')dx', and give a characterization of such symbol functions. Symbol formulae for adjoint operators and for composite operators are given.
Cite this article
Keisuke Uchikoshi, Symbol Theory of Microlocal Operators. Publ. Res. Inst. Math. Sci. 24 (1988), no. 4, pp. 547–584DOI 10.2977/PRIMS/1195174867