4

I'm using \lim_{\substack{n\to\infty\\t_n\to t}} to put two things under a limit.

But ideally I'd like the arrows to be directly underneath each other.

Can this be done?

(Something on the lines of using & in \begin{align} \end{align}).

1
  • You could use an whole aligned environment as subscript to the \lim macro, but the spacings are not really nice
    – user31729
    Commented Jul 10, 2015 at 11:16

2 Answers 2

3

\substack is based on subarray which can be modified as follows:

Sample output

\documentclass{article}

\usepackage{amsmath}
\makeatletter
\newenvironment{subxarray}{%
  \vcenter\bgroup
  \Let@ \restore@math@cr \default@tag
  \baselineskip\fontdimen10 \scriptfont\tw@
  \advance\baselineskip\fontdimen12 \scriptfont\tw@
  \lineskip\thr@@\fontdimen8 \scriptfont\thr@@
  \lineskiplimit\lineskip
  \ialign\bgroup\hfil
    $\m@th\scriptstyle##$&$\m@th\scriptstyle{}##$\hfil\crcr
}{%
  \crcr\egroup\egroup
}
\makeatother
\begin{document}

\begin{equation*}
  \lim_{\begin{subxarray}n&\to\infty\\t_n&\to t\end{subxarray}} X_{n}(t_n).
\end{equation*}

\end{document}
4
\documentclass{article}
\usepackage{tabstackengine}
\stackMath
\makeatletter
\renewcommand\TAB@delim[1]{\scriptscriptstyle#1}
\makeatother
\begin{document}
\[
\lim_{\alignShortunderstack{n\to&\infty\\t_n\to&t}} X_n(t_n)
\]
\end{document}

enter image description here

By modifying the preamble to include

\makeatletter
\renewcommand\TAB@delim[1]{\scriptstyle#1}
\makeatother
\setstackgap{S}{2pt}

the interstack gap is reduced from 3pt to 2pt and the limit is set in \scriptstyle:

enter image description here

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .