= Hörmander integral kernel condition
{c}
{title2=$\sup_{y\ne0}\int_{|x|>2|y|}|K(x-y)-K(x)|\,dx<\infty$}
This integral smoothness condition on a <convolution> kernel controls how translations change the kernel away from the translation scale. It need not imply differentiability. Coupled with an $L^2$ operator bound, it yields a <weak type (1,1)> bound through the <Calderón–Zygmund decomposition>. It is distinct from the bracket-generating condition for differential operators also named after Hörmander.
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