2

I have an equation of this kind:

\begin{equation*}
A_1 \rightarrow A_2 \rightarrow \dots \rightarrow A_N 
\end{equation*}

And I would like to add a $B_1$ under $A_1$, $B_2$ under $A_2$ and $B_N$ under $A_N$. My idea was to use the environment align:

\begin{align*}
&A_1 \rightarrow &A_2 \rightarrow \dots &\rightarrow A_N \\
&B_1 &B_2 &B_3
\end{align*}

However it does not work as I was imagined. I would like to find a way to keep the equation above unchanged somehow.

Any help will be very much appreciated!

6 Answers 6

5

I'd keep the equation* environment and use bespoke array environments to place B_1 below A_1, B_2 below A_2, etc.

enter image description here

\documentclass{article} % or some other suitable document class
\usepackage{amsmath} % for 'equation*' env.
%% macro with a bespoke 'array' env.:
\newcommand\mybox[2]{\begin{array}[t]{@{}c@{}}
                        \displaystyle #1 \\ \displaystyle #2 
                     \end{array}}

\begin{document}

\begin{equation*}
A_1 \rightarrow A_2 \rightarrow \dots \rightarrow A_N 
\end{equation*}

\begin{equation*}
\mybox{A_1}{B_1} \to \mybox{A_2}{B_2} \to \dots \to \mybox{A_N}{B_N}
\end{equation*}

\end{document}
1
  • 1
    Thanks a lot! I didn't know the environment array!
    – Onil90
    Apr 8 at 11:55
6

It's easy with tikz-cd:

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz-cd}

\begin{document}

\begin{equation*}
\begin{tikzcd}[column sep=1em,row sep=-0.5ex]
  A_1 \arrow[r] &
  A_2 \arrow[r] &
  \cdots \arrow[r] &
  A_N
\\
  B_1 & B_2 & & B_N
\end{tikzcd}
\end{equation*}

\end{document}

enter image description here

4

You can use the underset command. MWE:

\documentclass{report}

\usepackage{amsmath}

\begin{document}

\begin{equation*}
    \underset{B_1}{A_1} \rightarrow \underset{B_2}{A_2} \rightarrow \dots \rightarrow \underset{B_N}{A_N} \\
\end{equation*}

\end{document}
2
  • Thanks! The problem with \underset is that it reduces the sizes of $B_1$, $B_2$ and $B_N$...
    – Onil90
    Apr 8 at 13:02
  • Should be solved by inserting \displaymath where desired.
    – oliversm
    Apr 8 at 19:15
3

Another solution with equation* and stackengine:

    \documentclass{article}
    \usepackage{amsmath}
    \usepackage[usestackEOL]{stackengine}

    \begin{document}

    \begin{equation*}\stackMath\renewcommand{\Sstackgap}{3\jot}
    \stackunder{A_1}{B_1} \longrightarrow \stackunder{A_2}{B_2} 
    \longrightarrow \dots \longrightarrow \stackunder{A_N}{B_N}
    \end{equation*}

    \end{document} 

enter image description here

2
  • 1
    Really cool! Never heard of it before!
    – Onil90
    Apr 8 at 12:36
  • 1
    Thank you for your kind appreciation! Stackengine is indeed a very useful package.
    – Bernard
    Apr 8 at 12:39
2

You may use the IEEEeqnarray* environment from the IEEEtrantools package.

\documentclass{article}
\usepackage{amsmath}
\usepackage{IEEEtrantools}

\begin{document}
\begin{IEEEeqnarray*}{c'c'c'c'c} % ' provides 1em separation between columns. You may use other glues for shorter or wider separation
A_1 & \rightarrow & A_2 & \rightarrow \dots \rightarrow & A_N \\
B_1 & & B_2 & & B_3
\end{IEEEeqnarray*}
\end{document}

enter image description here

5
  • The spacing around the \to arrows isn't even. Is there a way to make the spacing more even?
    – Mico
    Apr 8 at 10:40
  • @Mico Do you mean the spacing around the dots? That's possible using additional columns.
    – Imran
    Apr 8 at 11:27
  • Thanks a lot! I wasn't aware of this!
    – Onil90
    Apr 8 at 11:53
  • @Imran - II was referring to the fact that there's more whitespace around the arrows in A_1 & \rightarrow & A_2 than in \rightarrow \dots \rightarrow.
    – Mico
    Apr 8 at 13:05
  • @Mico I don't know. They should be the same though.
    – Imran
    Apr 8 at 16:23
2

With tabularray:

\documentclass[border=3.141592, varwidth]{standalone}
\usepackage{tabularray}

\begin{document}
\[
\begin{tblr}{cells=c, colsep=2pt}
A_1 & \to & A_2 & \to & \cdots & \to & A_N \\
B_1 &     & B_2 &     &        &     & B_3
\end{tblr}
\]
\end{document}

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.