= Mollification of a divergence-forcing equation
{title2=$\Delta u_\sigma=\operatorname{div}(bu)_\sigma+(cu)_\sigma+f_\sigma$}
The distributional equation $\Delta u=\operatorname{div}(bu)+cu+f$ becomes the smooth interior equation $\Delta u_\sigma=\operatorname{div}(bu)_\sigma+(cu)_\sigma+f_\sigma$. The products are convolved as wholes. Only coefficient bounds on compact interior sets are needed, and the <divergence-forcing interior H1 estimate> provides a uniform first derivative bound.
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