[Tex/LaTex] Proof environment – line break after the “Proof.”

Question

I want to make the proof environment in amsthm package to auto add a line break right after the "Proof."

I tried the following code, which also removed the QED sign, but it doesn't work: No linebreak is added.

\makeatletter
\renewenvironment{proof}[1][\proofname]{\par
    \normalfont \topsep6\p@\@plus6\p@\relax
    \trivlist
    \item[\hskip\labelsep
        \itshape
        #1\@addpunct{.} \newline] }%\ignorespaces}
\makeatother

Answer 1

a manual way to drop to a new line immediately after the proof heading is to insert

$ $\newline

but it's possible to build on the existing proof definition and thereby retain the ability to use the \qedhere facility to move the "tombstone" up to the actual last line of the proof.

\documentclass{article}
\usepackage{amsmath,amsthm}

\newenvironment{myproof}[1][\proofname]{%
  \begin{proof}[#1]$ $\par\nobreak\ignorespaces
}{%
  \end{proof}
}

\begin{document}

\begin{proof}
  $ $\newline
    First line of my proof

    Intermediary lines of my proof:
  \begin{itemize}
   \item next-to-last line
   \item last line of my proof
  \qedhere
  \end{itemize}
\end{proof}

\begin{myproof}[Proof of my theorem]
    First line of my proof

    Intermediary lines of my proof:
  \begin{itemize}
   \item next-to-last line
   \item last line of my proof
  \qedhere
  \end{itemize}
\end{myproof}

\begin{myproof}
    First line of my proof

    Intermediary lines of my proof:
  \begin{itemize}
   \item next-to-last line
   \item last line of my proof
  \qedhere
  \end{itemize}
\end{myproof}

\end{document}