The shift theorem is often expressed in shorthand as

The shift theorem says that a delay in the time domain corresponds to
a linear phase term in the frequency domain. More specifically, a
delay of samples in the time waveform corresponds to the linear
phase term
multiplying the spectrum, where
. (To consider as radians per second
instead of radians per sample, just replace by so that
the delay is in seconds instead of samples.) Note that spectral magnitude
is unaffected by a linear phase term. That is,
.