So that what's new in Saussure's thinking about the relationship between signified and signifier is that the sign tied up in this relationship is both arbitrary and differential.
这就是索绪尔所贡献的了，能指和所指的关系，也就是符号的组成方式，是任意的，有差别的。
2
The global Fourier transform can also be obtained by switching (up to sign) the multiplication by a coordinate of the affine line and the differential operator with respect to this coordinate.