\documentclass{article} \input{../note-setup} \title{\LaTeX{} Note Template} \author{Author} \date{\today} \extrainfo{Github: \href{https://github.com/fenglielie/latexzero}{https://github.com/fenglielie/latexzero}} \begin{document} % \maketitle \makecover{../cover/cover.png} \section{Theorem, Proposition, Proof} \begin{theorem} If $1
n/p$, or $p=1$ and $m \ge n$, there exist a constant $C = C(m,n,\gamma,p)$, such that \begin{equation*} \Vert R^m u \Vert_{L^\infty(\Omega)} \le C d^{m-n/p} |u|_{W^m_p(\Omega)} \end{equation*} for all $u \in W^m_p(\Omega)$. \end{theorem} \begin{proof} First, we assume that $u \in C^m(\Omega) \cap W^m_p(\Omega)$. We can use the pointwise representation of $R^mu(x)$. \begin{align*} |R^mu(x)| ={} & m \left| \sum_{|\alpha| = m} \int_{C_x} k_{\alpha}(x,z) D^\alpha u(z)\,dz \right| \notag \\ \le{} & C \sum_{|\alpha|=m} \int_{\Omega} |x-z|^{-n+m} |D^\alpha u(z)|\,dz \notag \\ \le{} & C' d^{m-n/p} |u|_{W^m_p(\Omega)}. \end{align*} The proof can be completed via a density argument. \end{proof} \begin{theorem}[xxx] If $1
n/p$, or $p=1$ and $m \ge n$, there exist a constant $C = C(m,n,\gamma,p)$, such that \begin{equation*} \Vert R^m u \Vert_{L^\infty(\Omega)} \le C d^{m-n/p} |u|_{W^m_p(\Omega)} \end{equation*} for all $u \in W^m_p(\Omega)$. \end{theorem} \begin{proof}[\upshape\bfseries Proof of xxx] First, we assume that $u \in C^m(\Omega) \cap W^m_p(\Omega)$. We can use the pointwise representation of $R^mu(x)$. \begin{align*} |R^mu(x)| ={} & m \left| \sum_{|\alpha| = m} \int_{C_x} k_{\alpha}(x,z) D^\alpha u(z)\,dz \right| \notag \\ \le{} & C \sum_{|\alpha|=m} \int_{\Omega} |x-z|^{-n+m} |D^\alpha u(z)|\,dz \notag \\ \le{} & C' d^{m-n/p} |u|_{W^m_p(\Omega)}. \end{align*} The proof can be completed via a density argument. \end{proof} \begin{theorem*} If $1
n/p$, or $p=1$ and $m \ge n$, there exist a constant $C = C(m,n,\gamma,p)$, such that
\begin{equation*}
\Vert R^m u \Vert_{L^\infty(\Omega)} \le C d^{m-n/p} |u|_{W^m_p(\Omega)}
\end{equation*}
for all $u \in W^m_p(\Omega)$.
\end{theorem*}
\begin{proof}
First, we assume that $u \in C^m(\Omega) \cap W^m_p(\Omega)$. We can use the pointwise representation of $R^mu(x)$.
\begin{align*}
|R^mu(x)| ={} & m \left| \sum_{|\alpha| = m} \int_{C_x} k_{\alpha}(x,z) D^\alpha u(z)\,dz \right| \notag \\
\le{} & C \sum_{|\alpha|=m} \int_{\Omega} |x-z|^{-n+m} |D^\alpha u(z)|\,dz \notag \\
\le{} & C' d^{m-n/p} |u|_{W^m_p(\Omega)}.
\end{align*}
The proof can be completed via a density argument.
\end{proof}
\begin{proposition}
\begin{equation*}
Q^m u(x) = \sum_{|\lambda| < m} \left( \int_B \psi_\lambda(y) u(y)\,dy \right) x^\lambda
\end{equation*}
where $\psi_\lambda \in C_0^\infty(\mathbb{R}^n)$ and $\mathrm{supp}(\phi_\lambda) \in \overline{B}$.
\end{proposition}
\begin{proof}
This follows from xxx if we define
\begin{equation*}
\psi_\lambda(y) = \sum_{\alpha \ge \lambda,|\alpha|