# Vertical space between proof and theorem environments

When compiling my latex file, the space between the ending of theorem body and the word proof appears to be a bit much. I know how to individual manage this using \vspace, but I want to change the settings in the preamble so that even propositions, lemmas and corollaries have the same vertical distance between the starting of the proof. I have included my latex file here. Any help will be much appreciated.

\documentclass[12pt,a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage[left=3.50cm, right=3.0cm, top=3.0cm, bottom=3.0cm]{geometry}
\usepackage{enumitem}
\usepackage{amsthm}
\usepackage{amsmath}
\setlength{\parskip}{5mm}
\setlength{\parindent}{0mm}
\setlength{\skip\footins}{1.6cm}
\setlength{\footnotesep}{0.5cm}
\newtheorem{thm}{Theorem}[section]
\newtheorem{lemma}[thm]{Lemma}
\newtheorem{proposition}[thm]{Proposition}
\newtheorem{cor}[thm]{Corollary}
\theoremstyle{definition}
\newtheorem{defn}[thm]{Definition}
\newtheorem{exmp}[thm]{Example}
\newtheorem{remark}[thm]{Remark}
\newcommand{\prn}{\mathrel{\mathrm{prn}}}
\begin{document}
\begin{thm}
Let $G$ be a group with subgroups $H$ and $K$. Then $[H,K] \unlhd \langle H, K\rangle$
\end{thm}
\begin{proof}
Every element in $[H,K]$ belongs to $\langle H, K \rangle$ because of the way in which the elements of $\langle H, K \rangle$ are defined.
\end{proof}
\end{document}

• Could you please post a minimal working example of the code you are using so that everyone can know which packages are at stake ? – mvienney Mar 7 '17 at 17:52
• @mvienney I have edited my post to reflect what I need. – R Maharaj Mar 7 '17 at 18:05

You save 10 pt in vertical spacing with ntheorem default:

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsfonts, amssymb}
\usepackage[left=3.50cm, right=3.0cm, top=3.0cm, bottom=3.0cm]{geometry}
\usepackage{enumitem}
\usepackage{amsmath, amssymb}
\setlength{\parskip}{5mm}
\setlength{\parindent}{0mm}
\setlength{\skip\footins}{1.6cm}
\setlength{\footnotesep}{0.5cm}
\usepackage[amsmath, thmmarks]{ntheorem}

\theoremstyle{plain}
\theorembodyfont{\itshape}
\newtheorem{thm}{Theorem}[section]
\newtheorem{lemma}[thm]{Lemma}
\newtheorem{proposition}[thm]{Proposition}
\newtheorem{cor}[thm]{Corollary}

\theorembodyfont{\normalfont}
\newtheorem{defn}[thm]{Definition}
\newtheorem{exmp}[thm]{Example}
\newtheorem{remark}[thm]{Remark}

\theoremstyle{nonumberplain}
\theoremsymbol{ \ensuremath{\Box}}
\newtheorem{proof}{Proof}

\newcommand{\prn}{\mathrel{\mathrm{prn}}}

\begin{document}

\begin{thm}
Let $G$ be a group with subgroups $H$ and $K$. Then $[H,K] \unlhd \langle H, K\rangle$.
\end{thm}
%
\begin{proof}
Every element in $[H,K]$ belongs to $\langle H, K \rangle$ because of the way in which the elements of $\langle H, K \rangle$ are defined.
\end{proof}
%
\begin{defn}
A trivial definition
\end{defn}

\end{document}


• This looks really good but how can prevent the word theorem from being italicized? – R Maharaj Mar 8 '17 at 5:49
• @R Maharaj: Please see my updated answer. – Bernard Mar 8 '17 at 9:45

\documentclass{article}
\usepackage{amsthm}
\usepackage{thmtools,blindtext}
\declaretheorem{theorem}
\declaretheoremstyle[%
spaceabove=3pt,%reduce or increase between theorem and proof
spacebelow=20pt,%reduce or increase
qed=\qedsymbol%
]{mystyle}
\declaretheorem[name={Proof},style=mystyle,unnumbered,
]{pf}

\begin{document}

\begin{theorem}
\blindtext
\end{theorem}
\begin{pf}
BLAAAAAAAAAAAAAAAAAAAAAAA
\end{pf}
\begin{theorem}
\blindtext
\end{theorem}

\textbf{Normal}
\begin{proof}
\blindtext
\end{proof}

\end{document}

• the settings in amsthm for the space between theorem and proof assume that the default baselines and \parskip will not be changed. this answer redefines these to be fixed distances. those values may or may not be appropriate if the \linespread or \parskip is changed. they also don't allow any stretch if a page is broken "short" because of an unbreakable element (e.g., a math display) that doesn't fit and must be moved to the next page. – barbara beeton Mar 7 '17 at 18:31