\begin{definition}[Definition:Dipole]
Let $\phi \in \map \DD \R$ be a test function.
Let $\delta \in \map {\DD'} \R$ be the Dirac delta distribution.
Then for any $\phi$ the distributional derivative of $\delta$ is known as the '''dipole''' and is given by:
:$\ds \map {\delta'} \phi = - \map {\phi'} 0$
\end{definition}