2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/115135Given a Calderón--Zygmund (C--Z for short) operator $T$, which satisfies Hörmander condition, we prove that: if $T$ maps all the characteristic atoms to $WL^{1}$, then $T$ is continuous from $L^{p}$ to $L^{p}(1<p<\infty)$. So the study of strong continuity on arbitrary function in $L^{p}$ has been changed into the study of weak continuity on characteristic functions.9 pagesClassical Analysis and ODEs42B20text