[Tex/LaTex] How to add equation with cases inside the table

casesline-breakingtables

I want to include the complicated equation into one of the cells of my table. I am using tabular environment, additionally I have some multirows. I would like to add something like this:

\begin{table}   
   \centering
   \begin{tabular}{l||p{6.5cm}|p{6cm}|p{3cm}|}
     \multirow{2}{*}{Problem}
     & a=3 & description & something \\
     &
     \[ l= \begin{cases} 
        a when sth \\
        b when sth else \\
        c when elsewhere;
       \end{cases}
     \] 
     & & \\
  \end{tabular}
\end{table}

The problem is precisely when I need to use \\ in purpose of proper cases environment look. In such a case it simply (compiler) get frozen… until whole processor is 'consumed'. Anyway anyone knows how to put the function, equation with cases into table?

Best Answer

If I make a document from your fragments, it processes without error:

enter image description here

\documentclass{article}
\usepackage{amsmath,multirow}

\begin{document}
\begin{tabular}{cp{5cm}cc}
\multirow{2}{*}{Problem}
& equation 1 & description & something \\
& equation which contains cases
\[
l=
\begin{cases} 
a &\text{when sth }\\
b &\text{when sth else} \\
c &\text{when elsewhere;}
\end{cases}
\] & & \\
xx&yy&zz
\end{tabular}
\end{document}

Related Solutions

[Tex/LaTex] Use column-separator & (ampersand) inside \newenvironment

The problem is that the \begin{...} and \end{...} pair commands automatically create a "group" so that, in effect, the & and \\ are "out of scope" for the tabular, while inside the "production" environment they just show up at a place where the compiler is not expecting them.

A second problem with your definitions is that, even if they would work, they would be adding an extra \\ at the end of the tabular, adding an unwanted space at the end. Perhaps some more appropriate definitions would be

\documentclass[a4paper,10pt]{article}

\newcommand{\production}[1]{#1 ::= &}
\newenvironment{grammar}{\tabular{p{3cm}l}}{\endtabular}

\begin{document}
\begin{grammar}
\production{XmlStartTag} ... \\
\production{XmlOtherTag} ... \\
\production{XmlEndTag} ...
\end{grammar}
\end{document}

Note no \\ at the end of the last production. Also in the definition of the grammar you don't need to repeat the work of \begin/\end, and you can instead directly use \tabular and \endtabular.

[Tex/LaTex] Using “cases” inside “equation” gives error[with “amsmath” loaded]

In the displaymath mode, you can not use any paragraph triggering commands such as blank lines or \par commands. (Not a good idea, but you can use it inside the cases environment). Also you don't need to switch to text mode and then again to math mode. You can just use text on the text and leave the rest as it is.

Another point is the use of & characters which is the column delimiter that should be used inside the cases environment. This would be apparent if one of the cases starts with 1250 and the other is 1 which would lead to a bad alignment (try without the & characters!).

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
X(\omega) = \begin{cases}
1 &\text{se $\omega\in A$}\\
1250 &\text{se $\omega \in A^c$}
\end{cases}
\end{equation*}

\end{document}

enter image description here

Also mathtoolspackage provides some nice extensions and bugfixes of amsmath, so here is an example of dcases* environment which automatically switches to text mode in the second entry of the case declaration:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\[
X(\omega) = \begin{dcases*}
1 & se $\omega\in A$\\
0 & se $\omega \in A^c$
\end{dcases*}
\]
\end{document}

enter image description here

If you are using the standalone class (which gives errors) then you have to use it as

\documentclass[preview]{standalone}

Best Answer

Related Solutions

[Tex/LaTex] Use column-separator & (ampersand) inside \newenvironment

[Tex/LaTex] Using “cases” inside “equation” gives error[with “amsmath” loaded]

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