Friedel's law

Friedel's law, named after Georges Friedel, is a property of Fourier transforms of real functions.

Given a real function ${\displaystyle f(x)}$, its Fourier transform

has the following properties.

where ${\displaystyle F^{*}}$ is the complex conjugate of ${\displaystyle F}$.

Centrosymmetric points ${\displaystyle (k,-k)}$ are called Friedel's pairs.

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