 In this connection, the Riesz potential of a positive Borel measure μ with compact support is chiefly of interest in potential theory because "I"αμ is then a (continuous) subharmonic function off the support of μ, and is lower semicontinuous on all of R"n".Consideration of the Fourier transform reveals that the Riesz potential is a Fourier multiplier.In fact, one has
and so, by the convolution theorem,

The Riesz potentials satisfy the following semigroup property on, for instance, rapidly decreasing continuous functions
provided
Furthermore, if 2 

Gerontas

Family of the Athenian nobility of the late Byzantine and Ottoman years.