# Indentation in newtheorem environment

I already have a personalization of the "newtheorem" environment, as follows:

   \documentclass[a4paper,10pt]{article}
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{lmodern}
\usepackage[dvipdfm]{color}
\usepackage[francais]{babel}
\usepackage{textcomp}
\usepackage{framed}
\theoremstyle{definition}
\newtheorem{definitionT}{Définition}[section]
\newenvironment{definition}{\begin{leftbar}\begin{definitionT}\par\leavevmode\par\noindent}{\end{definitionT}\end{leftbar}} \begin{document}
\begin{definition}
Example
\end{definition}
\end{document}


It makes a left vertical black line along my environment "definition" I tried to make the text start at a new line and not to be indented, but it is slighlty indented. How could I get rid of this indentation?

I would like it to look like this:

• (1) welcome, (2) please provide a full minimal example, containing preamble etc. That makes it a LOT easier to help (update your question with the mwe) – daleif Oct 26 '15 at 22:09
• I don't think you can do \newenvironment{def}. – egreg Oct 26 '15 at 22:17
• @daleif Thanks for your recommendations (and your welcome). I edited my question, adding the preamble and modifying "def" to "definition" (it is "definition" in my .tex file). – MoebiusCorzer Oct 26 '15 at 22:37
• That is still not a minimal example, it has no body. Basically an mwe is a (in theory) fully compilable document, where others does not have to add anything in order to test the code. – daleif Oct 26 '15 at 22:40
• You might want to look into the following packages: mdframed or tcolorbox – daleif Oct 26 '15 at 22:40

You need \ignorespaces after \noindent; the space you see comes from the end-of-line after \begin{definition}.

\documentclass[a4paper,10pt]{article}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[francais]{babel}

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{lmodern}
\usepackage[dvipdfmx]{color} % better than dvipdfm
\usepackage{textcomp}
\usepackage{framed}

\theoremstyle{definition}
\newtheorem{definitionT}{Définition}[section]
\newenvironment{definition}
{\begin{leftbar}%
\begin{definitionT}%
\par\mbox{}\par\noindent\ignorespaces}
{\end{definitionT}%
\end{leftbar}}

\begin{document}

\begin{definition}
Example
\end{definition}

\end{document}


Without \ignorespaces it looks like this

• Doesn't that get you into problems if you start your theorem with a blank line in the code? Not that uncommon to see in some of the manuscripts that I edit. – daleif Oct 26 '15 at 23:21
• @daleif Of course. I just fixed the OP's problem. – egreg Oct 26 '15 at 23:24
• Then it is just a note for future visitors to this question. – daleif Oct 26 '15 at 23:25