[Tex/LaTex] Prevent line break before equation environment in enumerated list item

#enumerateequationsieeetran

Suppose I have something like

\begin{enumerate}
  \item 
    \begin{equation*} 
      some eq 
    \end{equation*}
  \item 
    \begin{IEEEeqnarray*}{l} 
      eq 1 \\ 
      eq 2 \\ 
      ... 
      eq n 
    \end{IEEEeqnarray*}
\end{enumerate}

how would one go about removing the resulting line break that occurs when the equation starts, for both single line and multi-lined equations, so that the equation and the item numbering are aligned together? I thought this would be a relatively common issue but I can't find another post related to it – preventing the line break when beginning an item in an enumerated list with a new environment.

Best Answer

Here are some alternative options for you:

enter image description here

\documentclass{IEEEtran}% http://ctan.org/pkg/ieeetran
\begin{document}
\begin{enumerate}
  \item First item
  \item
    \[
      f(x) = ax^2 + bx + c
    \]
  \item
    \begin{IEEEeqnarray*}{l} 
      f(x) \\ 
      ax^2 \\ 
      bx \\
      c
    \end{IEEEeqnarray*}
  \item Last item
\end{enumerate}
\begin{enumerate}
  \item First item
  \item $f(x) = ax^2 + bx + c$
  \item \hfill $f(x) = ax^2 + bx + c$ \hfill\mbox{}
  \item
    $\begin{array}[t]{@{}l@{}}
      f(x) \\ 
      ax^2 \\ 
      bx \\
      c
    \end{array}$
  \item \null\hfill
    $\begin{array}[t]{@{}l@{}}
      f(x) \\ 
      ax^2 \\ 
      bx \\
      c
    \end{array}$
    \hfill\null
  \item Last item
\end{enumerate}
\end{document}

If you wish to stretch the contents of the array, modify \arraystretch as discussed in Column padding in tables.

Related Solutions

[Tex/LaTex] How to remove unnecessary space in flalign* environment

Here is some lazy way:

\documentclass{article}
\date{}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage{tikz}
\addtolength{\oddsidemargin}{-.875in}
\addtolength{\evensidemargin}{-.875in}
\addtolength{\textwidth}{1.75in}
\addtolength{\topmargin}{-.875in}
\addtolength{\textheight}{1.75in}


\begin{document}
\textbf{Question 3.6.}
\begin{enumerate}
\setlength\abovedisplayskip{0pt}           %% new
\item $\mathcal{P}(\emptyset)=\{\emptyset\}$
\item \begin{minipage}[t]{\linewidth}      %% new
\vspace{-\baselineskip}
 \begin{flalign*}
\mathcal{P}\Big(\mathcal{P}\big(\mathcal{P}(\emptyset)\big)\Big)&=\mathcal{P}\Big(\mathcal{P}\big(\{\emptyset\}\big)\Big)&\\
\mathcal{P}\big(\{\emptyset\}\big)&=\big\{\emptyset ,\{\emptyset\}\big\}\\
\mathcal{P}\Big(\mathcal{P}\big(\mathcal{P}(\emptyset)\big)\Big)&=\mathcal{P}\big(\big\{\emptyset ,\{\emptyset\}\big\}\big)\\
&=\Big\{\emptyset , \{\emptyset\},\big\{\{\emptyset\}\big\}, \big\{\emptyset ,\{\emptyset\}\big\}\Big\}
\end{flalign*}
\end{minipage}                            %% new
\end{enumerate}
\end{document}

enter image description here

[Tex/LaTex] split equation in multiple lines

I suggest you use a split environment, which in contrast to multline may be used a subenvironment of equation. You need to specify an alignment point on each line with & and separate lines with \\. In this case the first line should be move left relative to the others and the package mathtools provides a convenient command for this:

Sample output

\documentclass{article}

\usepackage{mathtools}

\begin{document}

\begin{equation}
  \label{wave kinematic}
  \begin{split}
    \MoveEqLeft
    \frac{\partial N(\sigma;\lambda;\theta;t)}{\partial t}
    + \frac{\partial C_{g,\lambda}N(\sigma;\lambda;\theta;t)}
    {\partial \lambda} \\
    &+ \cos\phi^{-1} \cdot
    \frac{\partial C_{f,\phi}N(\sigma;\lambda;\theta;t)}{\partial
    \phi} \\
    &+ \frac{\partial C_{f,\theta}N(\sigma;\lambda;\theta;t)}{\partial
    \theta} 
    + \frac{\partial C_{f,\sigma}N(\sigma;\lambda;\theta;t)}{\partial
    \sigma}  
    = \frac{S(\sigma;\theta;\lambda;\varphi;t)}{\sigma}
  \end{split}
\end{equation}

\end{document}

I have split across three lines for clarity. If you wanted to just split in two parts, then multlined (notice the extra d) from the mathtools package would be a simpler solution:

multlined sample

\documentclass{article}

\usepackage{mathtools}

\begin{document}

\begin{equation}
  \label{wave kinematic}
  \begin{multlined}
    \frac{\partial N(\sigma;\lambda;\theta;t)}{\partial t}
    + \frac{\partial C_{g,\lambda}N(\sigma;\lambda;\theta;t)}
    {\partial \lambda} 
    + \cos\phi^{-1} \cdot
    \frac{\partial C_{f,\phi}N(\sigma;\lambda;\theta;t)}{\partial
    \phi} \\
    + \frac{\partial C_{f,\theta}N(\sigma;\lambda;\theta;t)}{\partial
    \theta} 
    + \frac{\partial C_{f,\sigma}N(\sigma;\lambda;\theta;t)}{\partial
    \sigma}  
    = \frac{S(\sigma;\theta;\lambda;\varphi;t)}{\sigma}
  \end{multlined}
\end{equation}

\end{document}

All the above works with elsarticle class in your updated question. E.g. the first version becomes:

\documentclass[authoryear,preprint,review,12pt]{elsarticle}

\usepackage{mathtools}

\begin{document}

\begin{equation}
  \label{wave kinematic}
  \begin{split}
    \MoveEqLeft
    \frac{\partial N(\sigma;\lambda;\theta;t)}{\partial t}
    + \frac{\partial C_{g,\lambda}N(\sigma;\lambda;\theta;t)}
    {\partial \lambda} \\
    &+ \cos\phi^{-1} \cdot
    \frac{\partial C_{f,\phi}N(\sigma;\lambda;\theta;t)}{\partial
    \phi} \\
    &+ \frac{\partial C_{f,\theta}N(\sigma;\lambda;\theta;t)}{\partial
    \theta} 
    + \frac{\partial C_{f,\sigma}N(\sigma;\lambda;\theta;t)}{\partial
    \sigma}  
    = \frac{S(\sigma;\theta;\lambda;\varphi;t)}{\sigma}
  \end{split}
\end{equation}

\end{document}

Best Answer

Related Solutions

[Tex/LaTex] How to remove unnecessary space in flalign* environment

[Tex/LaTex] split equation in multiple lines

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