alignamsmath
I'm using the \align* environment from the amsmath package. How can I center one of the lines inside the environment?
In the following example, I want to the \vdots to be centered, instead of awkwardly aligned with the b above it.
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align*}
& a = (a_1, a_2) \\
& b = (b_1, b_2) \\
& \vdots \\
& z = (z_1, z_2)
\end{align*}
\end{document}
Don't use align. Use gather instead.
\documentclass[fleqn]{article}
\usepackage{amsmath}
\begin{document}
\begin{gather}
b := (a \oplus s_1) \oplus s_2 \\
e := 0
\end{gather}
\end{document}
An aligned environment nested in an align solves the problem, if I understood well what you want:
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{align}
& \begin{aligned}X & = \text{first line} = \\
& = \text{second line}
\end{aligned} \\
& XX = \text{right side}
\end{align}
\end{document}
Added:
With the optional argument [b] for aligned, you obtain this layout of the equations numbers:
Best Answer