indentationproof-package
This is standard proof environmet.
But I want to indent the body of proof like this. How should I code?
This is my header.
\documentclass[a4paper,12pt,oneside]{book}
\usepackage[utf8]{inputenc}
\usepackage{graphicx}
\usepackage{titlesec,fancyhdr}
\usepackage{amssymb,amsmath,amsthm,amsfonts,cleveref,enumitem,thmtools}
\usepackage[no-math]{fontspec}
\usepackage{xcolor}
\usepackage{setspace,mathtools}
Like this?
\documentclass[11pt]{article}
\usepackage{amsthm,xpatch}
\xpatchcmd{\proof}{\hskip\labelsep}{\hskip5\labelsep}{}{} %% change 5 here as you wish
\begin{document}
\begin{proof}
This is the proof of the lemma This is the proof of the lemma This is the proof of the lemma This is the proof of the lemma This is the proof of the lemma
\end{proof}
\end{document}
You have to load xpatch package (by adding \usepackage{xpatch} in the preamble) and then add the following to your preamble:
\xpatchcmd{\proof}{\hskip\labelsep}{\hskip5\labelsep}{}{}
If you don't have xpatch installed, then add the following to your preamble (after \usepackage{amsthm})
\makeatletter
\renewenvironment{proof}[1][\proofname]{\par
\normalfont
\topsep6\p@\@plus6\p@ \trivlist
\item[\hskip5\labelsep\itshape
#1\@addpunct{.}]\ignorespaces
}{%
\qed\endtrivlist
}
\makeatother
The proof environment is not defined so you get the error
! LaTeX Error: Environment proof undefined.
a common way to define it is to load amsthm when you get a proof heading and qed box at the end.
\documentclass[12pt]{report}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{float}
\usepackage{framed}
\usepackage[hang,flushmargin]{footmisc}
\usepackage{amsthm}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{definition}{Definition}[section]
\begin{document}
\begin{proof}
Assume that $R$ decides $\mathrm{HALT}_{\mathrm{TM}}$, and obtain a contradiction. Construct $S$ to decide $A_{\mathrm{TM}}$, where $S$ operates as follows:
$S={}$ ``On input $\langle M, w \rangle$, an encoding of a TM $M$ and a string $w$:
\begin{enumerate}
\item Run TM $r$ on input $\langle M, w \rangle$.
\item If $R$ rejects, reject
\item If $R$ accepts, accept
\item If $M$ has accepted, accept; if $M$ has rejected, reject."
\end{enumerate}
If $R$ decides $\mathrm{HALT}_{\mathrm{TM}}$, then $S$ decides $A_{\mathrm{TM}}$. Because $A_{\mathrm{TM}}$ is undecidable, $\mathrm{HALT}_{\mathrm{TM}}$ must also be undecidable.
\end{proof}
\end{document}
Best Answer
You can redefine the
proofenvironment:Please, don't underline! Please! And don't indent either.