# Multi-page equations — problem

I have a very long derivation, that needs to look like:

A = B \\ = C \\ = D \\

etc. The derivation spans across many lines. I'm looking for a way to typeset it so that when it reaches the end of the page it can continue naturally on the next page, without trying to fit the entire equation into a single page. I'm currently using eqnarray and it insists that all its contents sit on a single page.

Can anyone suggest another environment that supports multi-page equations?

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Don't use eqnarray use align. I don't know if this solves that problem. But just in general, don't use eqnarray –  Seamus Aug 4 '11 at 16:08
Take a look at a special PracTeX Journal article to learn why not to use the eqnarray environment anymore. –  Thorsten Donig Aug 4 '11 at 16:14

With align, page breaks in multi line equations are possible. The command \allowdisplaybreaks enables it. You can fine-tune it optionally:

• \allowdisplaybreaks[1] : page breaks are allowed, but avoided if possible
• \allowdisplaybreaks[2], ..., \allowdisplaybreaks[4] : page breaks are allowed, more relaxed

You can still use \\* to forbid a page break at places where it's undesirable.

While \allowdisplaybreaks goes into the preamble, you could also allow page breaks at certain places in the body text by \displaybreak:

• \displaybreak[0] : allows a page break after the following \\, but doesn't encourage it
• \displaybreak[1], ..., \displaybreak[3] : allows a page breaks, more relaxed
• \displaybreak[4] : forces a page break after the following \\

4 is the default value for both \displaybreak and \allowdisplaybreaks.

See: 3.9 Vertical spacing and page breaks in multiline displays in the amsmath user's guide.

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