It is proved that the substitituon mapping is a proper Fourier integral operator with generalized hypoellipticity.
证明了变量替换映射是一个具广义亚椭园性的适的富里叶积分算子。
英语百科
Fourier integral operator
In mathematical analysis, Fourier integral operators have become an important tool in the theory of partial differential equations. The class of Fourier integral operators contains differential operators as well as classical integral operators as special cases.