Align environment

I'd like to ask how in align environment to number only one of the equations.

\begin{aligned}
\mathsf{E}[W^{i}_{t}-W^{i}_{s}]&=0,\\
1\le i,j\le n,\, 0\le s<t.
\end{aligned}


One more question. (The first one has already been sorted out). How can I break page in the align environment?

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Place a \notag command in each line that you do not wish numbered. –  azetina Jul 2 '12 at 19:08
Also, your exampled uses the aligned environment, did you mean to use align instead? –  Peter Grill Jul 2 '12 at 19:11
Try \allowdisplaybreaks in the preamble to allow page breaks. –  azetina Jul 2 '12 at 20:14

The aligned environment is a subsidiary math environment and thus can be used within another math environment. For example:

\begin{aligned} \mathsf{E}[W^{i}_{t}-W^{i}_{s}]&=0,\\ \mathsf{E}\big[[W^{i}_{t}-W^{i}_{s}][W^{j}_{t}-W^{j}_{s}]\big]&=q_{ij}(t-s),\quad 1\le i,j\le n,\, 0\le s<t. \end{aligned}


This automatically numbers the entire aligned group. But if you are just using it within  or  there is no numbering. Hence, to get the numbering right, rather use the the align environment as follows:

\documentclass[letterpaper]{article}
\usepackage{amsmath,amssymb}
\begin{document}

\begin{align}
\mathsf{E}[W^{i}_{t}-W^{i}_{s}]&=0,\\
1\le i,j\le n,\, 0\le s<t. \notag \\
\mathsf{E}[W^{i}_{t}-W^{i}_{s}]&=0,
\end{align}

\end{document}


Notice the employment of the \notag command to remove the numbering on desired lines.

This yields:

To work with the page breaks for the align environment, one can use \allowdisplaybreaks. For example:

\documentclass[letterpaper]{article}
\usepackage{amsmath,amssymb,lipsum}
\begin{document}
\lipsum[2-6]
{\allowdisplaybreaks
\begin{align}
\mathsf{E}[W^{i}_{t}-W^{i}_{s}]&=0,\\
1\le i,j\le n,\, 0\le s<t. \notag \\
\mathsf{E}[W^{i}_{t}-W^{i}_{s}]&=0,
\end{align}}
\end{document}


This gives:

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Thank you for your answer. It works fine now. –  Laura Jul 2 '12 at 20:12
@Jane You are most welcome. If you ever need further clarifications ask. –  azetina Jul 2 '12 at 20:14
I do. I modified the question. as well, I would need to break page in the align environment. –  Laura Jul 2 '12 at 20:16
Did \allowdisplaybreaks work for you? You can use it also in the form {\allowdisplaybreaks **align content here**} –  azetina Jul 2 '12 at 20:19
No, it doesn't work. Maybe i don't use it in the right way. However, I would prefer an automatic solution. –  Laura Jul 2 '12 at 20:27