[Tex/LaTex] `parskip` removes spacing before `amsthm` theorem environments

amsthmspacingtheorems

I have a spacing problem. Whenever I include a theorem environment, \begin{theorem}\end{theorem}, the theorem appears very close to the previous line. The spacing is much less than the normal spacing between lines. Do any one have any idea to change this? I don't just ad hoc add \vskip at each theorem environment.

Minimal not working example:

\documentclass[12pt,letterpaper]{article}

\usepackage{lmodern}
\usepackage[T1]{fontenc}

\usepackage{amsmath} % AMS mathmode stuff
\usepackage{amsthm}
\usepackage{parskip} % remove auto-indentation of paragraphs with \setlength{\parindent}{0pt}

\newtheorem{thm}{Theorem}
\newenvironment{theorem}[1][]{\begin{thm}[#1]\upshape}{\end{thm}}

\begin{document}

 \section{Test}

 Let there be nice spacing.

 \begin{theorem}
  No space for you!
 \end{theorem}

\end{document}

It produces the following as output:

Commenting out \usepackage{parskip} causes the following output to be produced:

Best Answer

Put the following code in the preamble:

\makeatletter
\def\thm@space@setup{%
  \thm@preskip=\parskip \thm@postskip=0pt
}
\makeatother

The problem is that amsthm sets \thm@preskip to \topsep, which is zeroed by parskip.

Related Solutions

[Tex/LaTex] Wrong spacing before theorem environment (amsthm)

I actually found out the answer to my question by going the ECM route.

What was causing the problem was that I was using the parskip package with the option parfill, so that paragraphs, instead of starting with a blank indent, would start with no indent but separated by a blank line. ECM:

\documentclass{article}
\usepackage{amsthm}
\newtheorem{theorem}{Theorem} % <-- Note this line?
\usepackage[onehalfspacing]{setspace}
\usepackage[parfill]{parskip}
\begin{document}
First paragraph

Second paragraph

Third paragraph
\begin{theorem}
  1+1=2
\end{theorem}

\end{document}

I found out that I wasn't the first one to have the problem. The solution is to add:

\begingroup
    \makeatletter
    \@for\theoremstyle:=definition,remark,plain\do{%
        \expandafter\g@addto@macro\csname th@\theoremstyle\endcsname{%
            \addtolength\thm@preskip\parskip
            }%
        }
\endgroup

in the preamble after calling the amsthm package. It will redefine the theorems environment (or any user-defined environment) by adding the warranted extra space at the beginning. The extra space is not hard-coded , so if you remove the parskip package from your preamble, everything returns to the default spacing: nice!

Hope this helps!

[Tex/LaTex] amsthm: how to reduce the vertical spacing between theorem and proof

One possibility would be to redefine the proof anvironment as defined in amsthm.sty (the definition uses \topsep6\p@\@plus6\p@\relax, so you could make some changes there). Another approach would be to use the front-end thmtools to define a new theorem-like structure behaving like the standard proof environment, but using the spaceabove key to control the vertical space above it. The following example illustrates this second approach and shows the different spacing for the new prf environment and the standard proof environment:

\documentclass{article} 
\usepackage{amsthm} 
\usepackage{thmtools}

\declaretheorem{theorem} 
\declaretheoremstyle[%
  spaceabove=-6pt,%
  spacebelow=6pt,%
  headfont=\normalfont\itshape,%
  postheadspace=1em,%
  qed=\qedsymbol%
]{mystyle} 
\declaretheorem[name={Proof},style=mystyle,unnumbered,
]{prf}

\begin{document} 

\begin{theorem} 
A really important result.
\end{theorem}
\begin{prf} 
And its proof with less space above.
\end{prf} 
\begin{theorem} 
A really important result.
\end{theorem}
\begin{proof} 
And its proof with too much space above.
\end{proof} 

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Wrong spacing before theorem environment (amsthm)

[Tex/LaTex] amsthm: how to reduce the vertical spacing between theorem and proof

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