Why does numcases uses a different bracket to cases?

Question

\documentclass{article}
\usepackage{amsmath}
\usepackage{cases}
\begin{document}
Cases:
\begin{equation}
\begin{cases}
    N + N/4  \\
    6-W_{|N|}
\end{cases}
\end{equation}
Numcases:
\begin{subnumcases}{}
    N +  N/4  \\
    6-W_{|N|}  
\end{subnumcases}
\end{document}

I would like to have the sub-numbering of subnumcases but with the standard bracket of cases.

You could try https://tex.stackexchange.com/a/165690/, possibly removing the \, after \empheqlbrace. — Marijn, Apr 25 '19 at 16:42

score 4 · Answer 1 · answered Apr 25 '19 at 17:14

You can use empheq which is better than cases for this task:

\documentclass{article}
\usepackage{amsmath}
\usepackage{empheq}

\usepackage{cases}
\begin{document}
\subsubsection*{Cases}
\[
\begin{cases}
    N +  N/4  \\
    6-W_{|N|}  
\end{cases}
\]
\subsubsection*{Numbered cases}
\begin{empheq}[left=\empheqlbrace]{align}
  &  N + N/4  \\
  &  6-W_{|N|}
\end{empheq}
\subsubsection*{Subnumbered cases}
\begin{subequations}
\begin{empheq}[left=\empheqlbrace]{align}
  &  N + N/4  \\
  &  6-W_{|N|}
\end{empheq}
\end{subequations}
\end{document}

You get the same alignment if you use

\[
\left\{
\begin{aligned}
    N +  N/4  \\
    6-W_{|N|}
\end{aligned}
\right.
\]

for the first.

Sebastiano · Answer 2 · 2019-04-25T18:49:46.853

0

Using for example, numcases instead of cases you will have the standard bracket. See the manual http://mirrors.ibiblio.org/CTAN/macros/latex/contrib/cases/cases.pdf pag. 2. The size is the same of the bracket.

\documentclass{article}
\usepackage{amsmath,verbatim}
\usepackage{cases}
\begin{document}
\begin{verbatim} 
 with numcases:
 \end{verbatim}

\begin{numcases}{}
 N + N/4  \\
 6-W_{|N|}
\end{numcases}
\begin{verbatim} 
with subnumcases:
\end{verbatim}    

\begin{subnumcases}{}
    N +  N/4  \\
    6-W_{|N|}  
\end{subnumcases}
\end{document}

edited Apr 25 '19 at 18:49

answered Apr 25 '19 at 16:32

Sebastiano

54,118

1

Doesn't this make both brackets wrong? Also numbering is now wrong. – Snobbish Hi-rep users Apr 25 '19 at 16:33
@valerie Now is it correct? – Sebastiano Apr 25 '19 at 16:43
No, look at bracket, they are totally different. Also your code and image are different. – Snobbish Hi-rep users Apr 25 '19 at 16:51
1

@valerie, curly braces are equal. however it seems that this fact Sebastiano emphasize with green rectangles using other tool on equation image. – Zarko Apr 25 '19 at 17:24
1

@Sebastiano, i suggest you to remove green rectangle from equation image. it seem that they confuse people. – Zarko Apr 25 '19 at 17:26
@Sebastiano No, these are the curly brackets from the numcase environment. They have a different height as in the normal case environment. The question explicitly asks for the brackets from the case environment. – Snobbish Hi-rep users Apr 25 '19 at 18:40
@Sebastiano Look at the correct output in the other answer, you can see that the brackets look different than yours. – Snobbish Hi-rep users Apr 25 '19 at 18:42
@Zarko Accept your precious suggestion. – Sebastiano Apr 25 '19 at 18:44
@Sebastiano Do you now see the wrong numbering and different size? – Snobbish Hi-rep users Apr 25 '19 at 18:56

score 0 · Answer 3 · answered May 11 '20 at 10:05

The literal answer to the question is that {cases} has invisible "struts", and the brace covers the extent of those. With {numcases} the brace only covers the mathematical text (the "ink").

You can make them equal by using

\usepackage[casesstyle]{cases}

This also normalizes the math style for both to be \displaystyle, where the amsmath version, based on {array}, is \textstyle (with compacted fractions and operators).

Why does numcases uses a different bracket to cases?

3 Answers3