3

I want to add brackets on one side of the equation and write something adjacent to it. But, I'm getting those words in the line below while I need those at one side of the equation. Can anyone help ?

$$w_t(t-1)=E_{t-1}P_t={}_{t-1}P_{t}^e=(1-\zeta )E(P_t|I_{t-1})+\zeta P_{t-1},0\leq \zeta \leq1$$
$$w_t(t-2)=E_{t-2}P_t={}_{t-2}P_{t}^e=(1-\zeta )E(P_t|I_{t-2})+\zeta P_{t-2},0\leq \zeta \leq 1$$
\raisebox{\depth}{$\Bigr\}\scriptstyle Difference in the information set in the 2 contracts $}

It's looking something like this, but I wanted the words and bracket to be at right side of both the equations.

I'm attaching for the same. enter image description here

8

Maybe rcases?

\documentclass{article}
\usepackage{mathtools} 
\begin{document}

\[
\begin{rcases}
\begin{array}{r@{}l}
w_t(t-1)&=E_{t-1}P_t={}_{t-1}P_{t}^e\\
&=(1-\zeta )E(P_t|I_{t-1})+\zeta P_{t-1},
\end{array}
&0\leq \zeta \leq1\\
\begin{array}{r@{}l}
w_t(t-2)&=E_{t-2}P_t={}_{t-2}P_{t}^e\\
&=(1-\zeta )E(P_t|I_{t-2})+\zeta P_{t-2},
\end{array}
& 0\leq \zeta \leq 1
\end{rcases}\begin{array}{l}
\text{Difference in the}\\
\text{information set in}\\
\text{the 2 contracts}
\end{array}
\]
\end{document}

enter image description here

  • Upvote for suggesting "rcases"...(it is new for me too... :-) ) – MadyYuvi May 27 at 4:58
  • 1
    If you used tabular instead of array, the \text “wrappers” wouldn’t be needed. :-) – Mico May 27 at 4:59
  • Really new concept, Thanks a lot! – Henam May 27 at 5:12
1

Some details of math typesetting are very important. For instance in

{}_{t-1}P_{t}^e

the “left subscript” would not descend as much as the “right subscript”. Some tricks are useful to achieve uniform appearance (mostly phantom superscripts).

Also the terms in the left-hand side should have lowered subscripts to match the others.

Spacing around = can be achieved with aligned, rather than array. The vertical bar should be \mid rather than |.

I use rcases wrapped around with a new environment that takes as arguments a clearance (optional, default 2em, meaning that at least half this clearance will appear at either side (useful if the left part is short, set it to a higher value) and the text that should appear to the right.

The text is typeset in a varwidth box with its maximum horizontal size determined by the width of the left part and the clearance.

\documentclass{article}
\usepackage{mathtools}
\usepackage{varwidth}

\usepackage{showframe} % just for the example

\newsavebox{\casesdescbox}
\newlength{\casesdescclearance}
\newenvironment{casesdesc}[2][2em]
 {%
  \setlength{\casesdescclearance}{#1}%
  \newcommand{\casesdescdesc}{#2}%
  \begin{lrbox}{\casesdescbox}
  $\begin{rcases}
 }
 {%
  \end{rcases}\,$
  \end{lrbox}%
  \usebox{\casesdescbox}%
  \begin{varwidth}{\dimexpr\displaywidth-\wd\casesdescbox-\casesdescclearance}
  \raggedright\casesdescdesc
  \end{varwidth}%
 }


\begin{document}

\[
\begin{casesdesc}{Difference in the information set in the two contracts}
\begin{aligned}[b]
w_t(t-1)&=E^{}_{t-1}P^{}_t={\vphantom{P}}^{}_{t-1}P_{t}^e\\
        &=(1-\zeta )E(P_t \mid I_{t-1})+\zeta P_{t-1},
\end{aligned}
& 0\leq \zeta \leq1 \\
\begin{aligned}[b]
w_t(t-2) &=E^{}_{t-2}P^{}_t={\vphantom{P}}^{}_{t-2}P_{t}^e\\
         &=(1-\zeta )E(P_t \mid I_{t-2})+\zeta P_{t-2},
\end{aligned}
& 0\leq \zeta \leq 1
\end{casesdesc}
\]

\[
\begin{casesdesc}[4em]{\small Difference in the information set in the two contracts}
\begin{aligned}[b]
w_t(t-1)&=E^{}_{t-1}P^{}_t={\vphantom{P}}^{}_{t-1}P_{t}^e\\
        &=(1-\zeta )E(P_t \mid I_{t-1})+\zeta P_{t-1},
\end{aligned}
& 0\leq \zeta \leq1 \\
\begin{aligned}[b]
w_t(t-2) &=E^{}_{t-2}P^{}_t={\vphantom{P}}^{}_{t-2}P_{t}^e\\
         &=(1-\zeta )E(P_t \mid I_{t-2})+\zeta P_{t-2},
\end{aligned}
& 0\leq \zeta \leq 1
\end{casesdesc}
\]

\end{document}

I show two example typesetting, one with smaller text size for the description and wider clearance.

The showframe package is used just to show the margins of the text block.

enter image description here

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