在框架定理環境之前和之後添加垂直空間

Question

我希望建立類似定理的環境，因為這是使它們從正文中脫穎而出的有效方法。

根據貢薩洛·梅迪納的回答對這個問題定理陳述周圍的方格，包\newmdtheoremenv中的命令mdframed就是正確的方法。

然而，我發現這種框架定理環境前後缺乏垂直空間（見下文）。我查看了mdframed文檔，但沒有找到任何可以解決此問題的內容。

我錯過了文檔中的某些內容嗎？

您將如何以簡單有效（自動）的方式解決這個問題？

是否有其他套件更mdframed適合框架定理環境？

\documentclass{book}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{mdframed}
\theoremstyle{definition}
\newmdtheoremenv{assum}{Assumption}[chapter]

\begin{document}

\chapter{Fluid mechanics}

\section{Fields}

The following fields are of particular interest:
\begin{itemize}
    \item $\rho$: fluid density (time-dependent scalar field);
    \item $p_{\text{tot}}$: total pressure in the fluid (time-dependent scalar field);
    \item $v$: velocity of the fluid parcels (time-dependent vector field).
\end{itemize}    

\begin{assum}[Differentiability of tensor fields]
    \label{assum:differentiability}
    All tensor fields of interest are differentiable (weakly, at least).
\end{assum}

Assumption~\ref{assum:differentiability} blah blah

\subsubsection{Mass-continuity equation}

The mass-continuity equation is derived from the principle of conservation of mass:
\begin{assum}[Conservation of mass]
    \label{assum:conservation_of_mass}
    Fluid density $\rho$ is a conserved quantity within fluid parcels:
if $V_{\text{fp}}(t)$ delimits a region of space occupied by a fluid parcel
at time $t$, then
    \begin{equation}
        \frac{\mathrm{d}\phantom{t}}{\mathrm{d}t}
\iiint_{ V_{\text{fp}}(t)} \rho \, \mathrm{d}V = 0\,.
    \end{equation}
\end{assum}
blablah

\end{document}

Answer 1

是的，您錯過了可以將選項傳遞給環境；特別是你可以使用skipabove=<length>，skipbelow=<length>：

\newmdtheoremenv[skipabove=\topsep,skipbelow=\topsep]{assum}{Assumption}[chapter]

你的例子：

\documentclass{book}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{mdframed}
\theoremstyle{definition}
\newmdtheoremenv[skipabove=\topsep,skipbelow=\topsep]{assum}{Assumption}[chapter]

\begin{document}

\chapter{Fluid mechanics}

\section{Fields}

The following fields are of particular interest:
\begin{itemize}
    \item $\rho$: fluid density (time-dependent scalar field);
    \item $p_{\text{tot}}$: total pressure in the fluid (time-dependent scalar field);
    \item $v$: velocity of the fluid parcels (time-dependent vector field).
\end{itemize}    

\begin{assum}[Differentiability of tensor fields]
    \label{assum:differentiability}
    All tensor fields of interest are differentiable (weakly, at least).
\end{assum}

Assumption~\ref{assum:differentiability} blah blah

\subsubsection{Mass-continuity equation}

The mass-continuity equation is derived from the principle of conservation of mass:
\begin{assum}[Conservation of mass]
    \label{assum:conservation_of_mass}
    Fluid density $\rho$ is a conserved quantity within fluid parcels: if $V_{\text{fp}}(t)$ delimits a region of space occupied by a fluid parcel at time $t$, then
    \begin{equation}
        \frac{\mathrm{d}\phantom{t}}{\mathrm{d}t} \iiint_{ V_{\text{fp}}(t)} \rho \, \mathrm{d}V = 0\,.
    \end{equation}
\end{assum}
blablah

\end{document}

這回答了您的前兩個問題；關於第三個，如果您的框架必須允許分頁，那麼可能性基本上是mdframed或 framed;這個問題對它們進行了比較：框架還是mdframed？ （優點缺點）。