The term energy has an important physical meaning in physics and is an extremely useful concept. A much more abstract
mathematical generalization is defined as follows. Let be a Space with Measure and let
be a real function on the Product Space
. When

exists for measures , is called the Mutual Energy and is called the Energy.

**References**

Iyanaga, S. and Kawada, Y. (Eds.). ``General Potential.'' §335.B in
*Encyclopedic Dictionary of Mathematics.* Cambridge, MA: MIT Press, p. 1038, 1980.

© 1996-9

1999-05-25