Definition:Fourier Transform/Real Function/Also known as

Fourier Transform of Real Function: Also known as
The real Fourier transform function is sometimes referred to as the minus-$i$ transform of $\map f t$.

This allows us to distinguish between this and the real inverse Fourier transform function, known in turn as the plus-$i$ transform of $\map F s$.

, in his of $1978$, discusses all $3$ of the formulations given in, referring to them as System $1$, System $2$ and System $3$.

The numbers assigned to Formulation $1$, Formulation $2$ and Formulation $3$ have been configured so as to correspond to these directly.