I have the following code sample:
\begin{align}
\pi^{(1)}_{i j} \enspace & = \enspace -\frac{1}{4}\eta^{\lambda \sigma} \left( \eta^{\mu \alpha}\eta^{\nu \beta} + \eta^{\mu \beta}\eta^{\nu \alpha} \right) \biggl\{ \frac{1}{2}\delta_{\lambda 0}( \delta_{\mu i}\delta_{\nu j} + \delta_{\mu j}\delta_{\nu i} ) \biggr\} \partial_{\sigma} h_{\alpha \beta}
\nonumber
\\
-\frac{1}{4}\eta^{\lambda \sigma} \left( \eta^{\mu \alpha}\eta^{\nu \beta} + \eta^{\mu \beta}\eta^{\nu \alpha} \right) \biggl\{ \frac{1}{2}\delta_{\sigma 0}( \delta_{\alpha i}\delta_{\beta j} + \delta_{\alpha j}\delta_{\beta i} ) \biggr\} \partial_{\lambda} h_{\mu \nu}
\mspace{-458mu}
\nonumber
\\
& = \enspace -\frac{1}{4}\partial^{\lambda} h^{\mu \nu}\delta_{\lambda 0}( \delta_{\mu i}\delta_{\nu j} + \delta_{\mu j}\delta_{\nu i} ) -\frac{1}{4}\partial^{\sigma} h^{\alpha \beta}\delta_{\sigma 0}( \delta_{\alpha i}\delta_{\beta j} + \delta_{\alpha j}\delta_{\beta i} )
\nonumber
\\
& = \enspace -\frac{1}{2}\partial^0 h^{i j} - \frac{1}{2}\partial^0 h^{i j}
\nonumber
\\
& = \enspace \dot{h}_{i j}
\end{align}
which gives the output:
As you see, I have a problem in aligning the lines properly which I tried to handle by using \mspace{}
. My first question is: What is the correct or proper way of doing this in these kind of lengthy equations?
I also have another problem. When I use separate \align
environments repeatedly, at some moment I reach to the end of the page and the last \align
environment automatically starts from a new page. In such a case all vertical spaces of the previous page changes and they ruin the proper format of the text. So, my second question is: How to properly arrange line breaks or spacing in repeated \align
environments consisting lengthy equations?