Is gather* equivalent to displaymath?

Question

Is gather* with one line of math equivalent to displaymath?

Does this question regarding difference between displaymath and equation environments answer your question? — Peter Grill, Nov 02 '11 at 19:14
By "equivalent", do you mean in terms of spacing and alignment (both vertical and horizontal)? — Werner, Nov 02 '11 at 19:24

score 10 · Accepted Answer · answered Nov 02 '11 at 19:38

No, it is not: the vertical spaces before and after the display are different.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\noindent Text
\begin{gather*}
  a=b
\end{gather*}
Text
\begin{displaymath}
  a=b
\end{displaymath}
Text
\end{document}

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score 1 · Answer 2 · answered Jun 05 '13 at 22:11

Also, if you have a very long equation in a \[...\], the space between the binary operators (like + and \times) will shrink to make the equation break the margin as little as possible (as happens with an equation in an ordinary paragraph; I'm assuming you're using Computer Modern fonts here). This space never shrinks inside a \begin...\end{gather*}.

This space also shrinks when necessary in an equation in \begin...\end{equation}, and never in an equation in \begin...\end{gather}.

By the way, very old versions of amsmath did define \[...\] and \begin...\end{equation} as a one-line \begin...\end{gather*} and \begin...\end{gather}, respectively. See "Changes in amsmath 2.0" here. The first edition (1994) of The LaTeX Companion is no longer correct about \[...\] and \begin...\end{equation} (see page 243).

Is gather* equivalent to displaymath?

2 Answers2

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