Math Formation/Graphical Visualization of a function with many included functions

Question

I hope I can put this the right way:

What I want from LaTeX is for example:

Example

a+b*c=  
| a=1+2  
| b=g*2+3  
||g=2b  
|||g=3  
|c= 4+d  
||d=3

and the | should be connected. Like a normal list with tabulator spaces.

Or if there is another way to show an equation as some kind of graphic that is connected.

What I found was xypic but this is not really what I'm looking for.

I could do it with a table, with the first column being connected and in there's a big vertical line, ….

Do you know something? Do you have any tip?

This is not just for pure maths.

I have revised the solution to show how math axis can be placed in the middle, for either an odd number or an even number of rows being stacked. — Steven B. Segletes, Jul 08 '13 at 19:39

score 4 · Answer 1 · edited Mar 20 '17 at 19:18

Here's another possibility:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\begin{align}
    a&+b*c = \\
    &\left|\begin{aligned}
        a&=1+2\\
        b&=g*2+3\\
        &\left|\begin{aligned}
            g&=2b\\
            &\left|\begin{aligned}
                g=3
            \end{aligned}\right.\\
        \end{aligned}\right.\\
        c&= 4+d\\
        &\left|\begin{aligned}
            d=3
        \end{aligned}\right.\\
    \end{aligned}\right.
\end{align}
\end{document}

enter image description here

Steven B. Segletes · Accepted Answer · 2013-07-08T19:38:09.270

The spacing between the rules is settable, in the definition of \lbar, currently set to 0.7ex. Below, I show it with either the math axis on the bottom line, the top line, or in the middle (odd # rows, then even # rows), respectively.

The keys are \Longstack which stacks above the baseline with uniform inter-row spacing, \Longunderstack which stacks from the baseline downward, with uniform interrow spacing, and (for the last example) \stackanchor which (for \stacktype "L")moves the aggregate baseline halfway between the baseline of the upper and lower items.

\documentclass{article}
\usepackage{stackengine}
\def\lbar{%
  \protect\rule[-.3\baselineskip]{.1ex}{\baselineskip}%
  \protect\rule{.7ex}{0ex}%
}
\begin{document}
\[
x = 
\Longstack[l]{%
{$a+b*c$}
{\lbar $a = 1 + 2$}
{\lbar $b = g*2 + 3$}
{\lbar\lbar $g = 2b$}
{\lbar\lbar\lbar $g = 3$}
{\lbar $c = 4 + d$}
{\lbar $d = 3$}%
}
\]

\[
x = 
\Longunderstack[l]{%
{$a+b*c$}
{\lbar $a = 1 + 2$}
{\lbar $b = g*2 + 3$}
{\lbar\lbar $g = 2b$}
{\lbar\lbar\lbar $g = 3$}
{\lbar $c = 4 + d$}
{\lbar $d = 3$}%
}
\]

\[
x=
\savestack{\upperstack}{\Longstack[l]{%
{$a+b*c$}
{\lbar $a = 1 + 2$}
{\lbar $b = g*2 + 3$}
{\lbar\lbar $g = 2b$}%
}}
\Longunderstack[l]{%
{\upperstack}
{\lbar\lbar\lbar $g = 3$}
{\lbar $c = 4 + d$}
{\lbar $d = 3$}%
}
\]

\[
x=
\savestack{\upperstack}{\Longstack[l]{%
{$a+b*c$}
{\lbar $a = 1 + 2$}
{\lbar $b = g*2 + 3$}%
}}
\savestack{\lowerstack}{\Longunderstack[l]{%
{\lbar\lbar $g = 2b$}
{\lbar\lbar\lbar $g = 3$}
{\lbar $c = 4 + d$}%
}}
\def\stackalignment{l}
\def\stacktype{L}
\stackanchor{\upperstack}{\lowerstack}
\]
\end{document}

enter image description here

Great possibility. But I don't get it working. I have MikTex 2.ß and texmaker running.
I always get: ! LaTeX Error: File `readarray.sty' not found.

What am I doing wrong? — Tim Kaluza, Jul 08 '13 at 18:19
@TimKaluza Your installation does not have the readarray package. It can be found at http://ctan.org/pkg/readarray. You can download the sty file into your current directory to get it working, but in the longer run, you ought to place it into your "local repository" (and update the FileName DataBase [FNDB]). That repository should be found at, by default, C:\Users\[your user name]\AppData\Roaming\MiKTeX\2.9\tex\latex — Steven B. Segletes, Jul 08 '13 at 18:23
@TimKaluza No problem. Glad to help. V1 of readarray only came out in late March. We're up to V1.2 currently. — Steven B. Segletes, Jul 08 '13 at 18:32
But you can't put the whole equation in math mode like [..]\ in John Wickerson's solution, do you? I prefer still this as the solution because of being a bit easier to write as the other one. — Tim Kaluza, Jul 08 '13 at 18:48
@TimKaluza Yes, it can be issued in math mode. The question is where do you want the math axis? I'll revise my solution to demonstrate. — Steven B. Segletes, Jul 08 '13 at 18:55

score 3 · Answer 3 · edited Apr 13 '17 at 12:35

Here's one possibility, obtained by modifying an old answer by Steven Segletes about how to format an email conversation (https://tex.stackexchange.com/a/121987/25356).

\documentclass{article}

\usepackage{scalerel}
\global\newcounter{embedlevel}
\global\newlength\embedspace
\embedspace=3ex
\setcounter{embedlevel}{1}

\newcommand\embed[1]{%
  \stepcounter{embedlevel}%
  \stretchrel{\rule{0.2ex}{1ex}}{\hspace{\embedspace}\parbox{%
    \textwidth-\value{embedlevel}\embedspace}{%
    \rule{0ex}{2ex}$#1$\rule[-1.3ex]{0ex}{1.3ex}%
  }}%
  \vspace{.5ex}%
  \addtocounter{embedlevel}{-1}%
}

\parindent=0pt

\begin{document}
\[
\begin{array}{l}
a+b*c=\\
\embed{%
  a=1+2 \\ 
  b=g*2+3\\
  \embed{%
    g=2b\\
    \embed{%
    g=3
    }%
  }\\
  c= 4+d\\
  \embed{%
    d=3
  }%
}
\end{array}
\]

\end{document}

enter image description here

Math Formation/Graphical Visualization of a function with many included functions

Example

3 Answers3