平移方程式而不改变标签

Question

我想知道如何在不改变标签位置的情况下平移方程式。使用 \hspace{2cm} 会出现下图所示的情况。我使用的代码是：

\documentclass[10pt,leqno,  a4paper]{report}
\usepackage[all, cmtip]{xy}
\usepackage{amscd,verbatim}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{leftidx}
\usepackage{amsfonts}
\usepackage{calligra}
\usepackage{sectsty}
\usepackage{lipsum}
\usepackage{fancyhdr}
\usepackage{imakeidx}
\usepackage[nottoc]{tocbibind}
\usepackage{etoolbox}
\makeindex[program=makeindex, options={-s indexstyle.ist}]
\usepackage[colorlinks = true,
linkcolor = blue]{hyperref}
\chapterfont{\centering \large}
\sectionfont{\small}
\usepackage[top=3cm,bottom=3cm,left=4cm,right=3cm]{geometry}
\pagestyle{fancy}
\renewcommand{\sectionmark}[1]{\markright{\thesection\ #1}{}}
\renewcommand{\chaptermark}[1]{\markboth{\thechapter\ #1}{}}
\fancyhf{} \fancyhead[LE,RO]{\thepage}
\fancyhead[C]{\rightmark}
\fancyhead[C]{\leftmark}
\renewcommand{\headrulewidth}{0pt}
\addtolength{\headheight}{5.0pt}
\usepackage[explicit]{titlesec}
\titleformat{\chapter}[display]
{\normalfont}{\centering\Large\chaptertitlename\ \thechapter}{25pt}
{\centering\LARGE\bfseries #1}
\titlespacing*{\chapter}
{-10pt}{25pt}{35pt}
\newcommand{\ssection}[1]{\section[#1]{\centering #1}}
\renewcommand{\theequation}{\thesection.\arabic{equation}}
\newenvironment{proof}{\smallskip \noindent{\bf Proof}: }
{\hfill \rule{0.25cm}{0.25cm}}
\newcommand\Id{\operatorname{Id}}



\begin{document}
\noindent Suppose $\phi:X \longrightarrow Y$ is a $b-$fibration of compact 
manifolds with corners. Then set

\begin{eqnarray}
\ \ \ \ \mathcal{V}_\phi(X) =\left\{
\begin{array}{c}
V \in \mathcal{V}_b(X): V \hbox{ \ is tangent to each leaf of  \ } \phi 
\hbox{ \ and the}\\
\hbox{ \   leaves of its restriction to each of the boundary faces of \ } X
\end{array}%
\right\}\index{$\mathcal{V}_\phi(X)$}
\end{eqnarray}%

\noindent Suppose $\phi:X \longrightarrow Y$ is a $b-$fibration of compact 
manifolds with corners. Then set

\begin{eqnarray}
\hspace{2cm} \mathcal{V}_\phi(X) =\left\{
\begin{array}{c}
V \in \mathcal{V}_b(X): V \hbox{ \ is tangent to each leaf of  \ } \phi 
\hbox{ \ and the}\\
\hbox{ \   leaves of its restriction to each of the boundary faces of \ } X
\end{array}%
\right\}\index{$\mathcal{V}_\phi(X)$}
\end{eqnarray}%

 \end{document} 

Answer 1

我怀疑你正在寻找这样的东西：

\documentclass[leqno]{article}
\usepackage{amsmath}

\usepackage{lipsum}
%-------------------------------- show page layout, only for test
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.15pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%

\begin{document}
\lipsum*[11]
\begin{equation}\label{2.7.1}
\cal V_\phi(X)
    = \left\{\begin{tabular}{@{}l@{}}
        $V \in \mathcal{V}_b(X):\ V$ is tangent to each leaf of  $\phi$  and the\\
        leaves of its restriction to each of the boundary faces of $X$
            \end{tabular}\right\}
\index{$\mathcal{V}_\phi(X)$}
\end{equation}
\lipsum*[11]
\begin{equation}\label{2.7.1}
\cal V_\phi(X)
    = \left\{\begin{tabular}{@{}l@{}}
        $V \in \mathcal{V}_b(X):\ V$ is tangent to each leaf of  $\phi$  and the\\
        leaves of its restriction to each of the boundary faces of $X$
            \end{tabular}\right\}
\end{equation}
\end{document}