The Riesz potential of order is the integral operator
defined whenever the integral converges, where is the Euclidean
norm and
is the normalization constant. It is a convolution
with a power-law kernel. With the Fourier transform
convention using
,
its Fourier multiplier is
.
For
with
and
,
this is the inverse potential associated with the fractional
Laplacian (Mei and Wei 2026).