4

LaTeX beginner here. I am currently trying to reproduce the following equations (with labels and the corresponding tags) using the report class and amsmath:

enter image description here

Simply reproducing the equations without the braces is rather simple:

\begin{align}
    \mathlarger{X_{ij}} &= \mathlarger{\frac{Y_iE_j}{Y}\left(\frac{t_{ij}}{\Pi_iP_j}\right)^{1-\sigma}} \tag{2-1} \label{eq:AvW1GE}\\
    \nonumber \\ 
    \mathlarger{(\Pi_i)^{1-\sigma}} &= \mathlarger{\sum_j \left(\frac{t_{ij}}{P_j}\right)^{1-\sigma} \frac{E_j}{Y}} \tag{2-2} \label{eq:AvW2GE}\\
    \nonumber\\
    \mathlarger{(P_j)^{1-\sigma}} &= \mathlarger{\sum_i \left(\frac{t_{ij}}{\Pi_i}\right)^{1-\sigma} \frac{Y_i}{Y}} \tag{2-3} \label{eq:AvW3GE}
\end{align}

However, adding the curly braces with text is more difficult for me. So far, I have tried to use "cases" with "aligned", providing at best mixed results, at least when it comes to adding the second brace, and error messages when adding tags or labels.

I would appreciate any help!

Best, Noah

4
  • Welcome to TeX.SE. Do the equations have to be numbered? Please advise.
    – Mico
    Mar 14, 2021 at 11:20
  • Hello Mico. Yes, at least it would be really helpful.
    – NoahDaniel
    Mar 14, 2021 at 11:22
  • What does the 2 in equation numbers represent?
    – Bernard
    Mar 14, 2021 at 11:43
  • It is just a reference for equation 1, 2, 3 in chapter 2, although for me it would be sufficient to simply lable the equations as (1) (2) and (3).
    – NoahDaniel
    Mar 14, 2021 at 11:45

5 Answers 5

4

A solution with empheq and stackengine:

\documentclass{report}
\usepackage{relsize}
\usepackage[usestackEOL]{stackengine} 
\usepackage{empheq}
\renewcommand{\theequation}{\thechapter-\arabic{equation}}

\begin{document}
\setcounter{chapter}{2}

\begin{empheq}[left=\Centerstack{\em Conditional \\ \em GE}: \empheqlbrace]{align}
  \textit{ Direct (PR): }\Biggl\{ \mathlarger{X_{ij}} &= \mathlarger{\frac{Y_iE_j}{Y}\left(\frac{t_{ij}}{\Pi_iP_j}\right)^{\mkern-5mu 1-\sigma}} \label{eq:AvW1GE}\\
    \nonumber \\
    \mathlarger{(\Pi_i)^{1-\sigma}} &= \mathlarger{\sum_j \left(\frac{t_{ij}}{P_j}\right)^{\mkern-5mu 1-\sigma} \frac{E_j}{Y}} \label{eq:AvW2GE}\\
    \nonumber\\
    \mathlarger{(P_j)^{1-\sigma}} &= \mathlarger{\sum_i \left(\frac{t_{ij}}{\Pi_i}\right)^{\mkern-5mu 1-\sigma} \frac{Y_i}{Y}} \label{eq:AvW3GE}
\end{empheq}

\end{document}

enter image description here

5
  • This works perfect. Thank you, Bernard!
    – NoahDaniel
    Mar 14, 2021 at 12:47
  • Hey Bernard, just one followup question: Is there any chance you know how to align the whole equation to the left so that the three equations are placed more to the center? I quickly tried out the \shoveleft command of the documentation which does not seem to work for me.
    – NoahDaniel
    Mar 14, 2021 at 13:04
  • 1
    @NoahDaniel: The only solution I could find was to add \hskip -2cm just before \Centerstack in the optional argument of the empheq environment. Looks like a hack, but the standard solutions (the fleqn environment from nccmath of replacing align with flalign did not work).
    – Bernard
    Mar 14, 2021 at 14:31
  • Great, thank you again for your help :)
    – NoahDaniel
    Mar 14, 2021 at 16:28
  • 1
    You could also use \mathllap{...} on the left-hand "column". Mar 15, 2021 at 0:45
4

If you are willing to do some manual fiddling to get the size and the position of the braces right, you can use the bigdelim package:

\documentclass{article}
\usepackage{amsmath}
\usepackage{relsize}
\usepackage{bigdelim}
\numberwithin{equation}{section}
\begin{document}

\begin{align}
\raisebox{5mm}{\ldelim\{{12}{*}[\emph{Conditional GE:}]}
 & \raisebox{5mm}{\ldelim\{{3}{*}[\emph{Direct(PE):}]}
   & \mathlarger{X_{ij}} &= \mathlarger{\frac{Y_iE_j}{Y}\left(\frac{t_{ij}}{\Pi_iP_j}\right)^{1-\sigma}} \tag{2-1} \label{eq:AvW1GE}\\
    \nonumber \\ 
 & & \mathlarger{(\Pi_i)^{1-\sigma}} &= \mathlarger{\sum_j \left(\frac{t_{ij}}{P_j}\right)^{1-\sigma} \frac{E_j}{Y}} \tag{2-2} \label{eq:AvW2GE}\\
    \nonumber\\
 & & \mathlarger{(P_j)^{1-\sigma}} &= \mathlarger{\sum_i \left(\frac{t_{ij}}{\Pi_i}\right)^{1-\sigma} \frac{Y_i}{Y}} \tag{2-3} \label{eq:AvW3GE}
\end{align}

\end{document}

enter image description here

4
  • By the way, this is not working for me. When I use your example, the two braces are directly aligned behind each other before the first equation with the usual size of the curly brace.
    – NoahDaniel
    Mar 29, 2021 at 11:21
  • @NoahDaniel Which version of bigdelim.sty and multirow.sty do you have? Mar 29, 2021 at 13:10
  • bigdelim 2019/05/31 v2.5 and multirow 2019/05/31 v2.5. And I am working with Overleaf, which uses TeX Live 2020, just in case this is important.
    – NoahDaniel
    Mar 29, 2021 at 14:19
  • I just realised that there are newer versions available. So probably this is the issue...
    – NoahDaniel
    Mar 29, 2021 at 14:44
2

Here's a solution that assigns a single equation number to all three rows.

enter image description here

IMNSHO, the tall parentheses produced by \left( and \right) are needlessly, and distractingly, large; that's why I use \Bigl( and \Bigr) in the code below. I also didn't employ any \mathlarger directives.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\text{Conditional GE: } 
\left\{
\begin{aligned}
\text{Direct (PE)}\qquad
X_{ij} &= \frac{Y_iE_j}{Y}\Bigl(\frac{t_{ij}}{\Pi_iP_j}\Bigr)^{\!1-\sigma} \\
(\Pi_i)^{1-\sigma} &= \sum_j \Bigl(\frac{t_{ij}}{P_j}\Bigr)^{\!1-\sigma} \frac{E_j}{Y} \\
(P_j)^{1-\sigma} &= \sum_i \Bigl(\frac{t_{ij}}{\Pi_i}\Bigr)^{\!1-\sigma} \frac{Y_i}{Y}
\end{aligned}
\right.
\end{equation}
\end{document}
0
2

The following uses the cases-package.

\documentclass{report}
\usepackage{amsmath}
\usepackage{cases}
\renewcommand{\theequation}{\thechapter-\arabic{equation}}


\begin{document}
   \setcounter{chapter}{2}
   
   \begin{numcases}{\text{Conditional GE}:}
      \text{Direct PE:}\bigg\{ & $\displaystyle X_{ij} = \frac{Y_{i}E_{j}}{Y}\left(\frac{t_{ij}}{\Pi_iP_j}\right)^{1-\sigma}$\\
                               & $\displaystyle \Pi_{i}^{1-\sigma} = \sum_{j}\left(\frac{t_{ij}}{P_j}\right)^{1-\sigma}\frac{E_j}{Y}$\\
                               & $\displaystyle P_{j}^{1-\sigma} = \sum_{i}\left(\frac{t_{ij}}{\Pi_{i}}\right)^{1-\sigma}\frac{Y_i}{Y}$
   \end{numcases}
\end{document}

The \displaystyle-command makes the symbols appear in "normal size" and not in textsize. enter image description here

0
2

Here is a solution with the environment {DispWithArrows} of witharrows.

\documentclass{report}
\usepackage{amsmath}
\usepackage{witharrows}
\renewcommand{\theequation}{\thechapter-\arabic{equation}}


\begin{document}
\setcounter{chapter}{2}

\begin{DispWithArrows}<\text{Conditional GE}:>[displaystyle]
\text{Direct PE:}\bigg\{ &  X_{ij} = \frac{Y_{i}E_{j}}{Y}\left(\frac{t_{ij}}{\Pi_iP_j}\right)^{1-\sigma}\\
                         &  \Pi_{i}^{1-\sigma} = \sum_{j}\left(\frac{t_{ij}}{P_j}\right)^{1-\sigma}\frac{E_j}{Y}\\
                         &  P_{j}^{1-\sigma} = \sum_{i}\left(\frac{t_{ij}}{\Pi_{i}}\right)^{1-\sigma}\frac{Y_i}{Y}
\end{DispWithArrows}
\end{document}

Output of the above code

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