LaTeX forum ⇒ Math & Science ⇒ Proper alignment of cases within align environment possible?

[Phillip]

Dear community,

there are several equations with domains. Some of these equations include cases.

Do you know any way that allows a consistent horizontal alignment of the domains?

The environment cases inside align results in that domains are not aligned at the same position.

Example

\begin{align}
a_i &=
\begin{dcases}
b_i & i \leq 0 \\
c_i & i < 0
\end{dcases} \\
d_i &= e_i &\forall i
\end{align}

Thank you in advance and happy New Year!
Phillip

[Johannes_B]

High and welcome, i did not test your example, because it is not compilable and my battery is low. But you are ending the line after the casses environment with a double backslash. If i understood you correctly, you need to write »for all i« just before ending the line, i.e. \end{cases} \forall i \\

[Phillip]

Thanks for your quick response!

I think I did not clearly present the problem.

Please take a look at this picture. It is a photo montage. It shows what the result should look like. You can see that equality signs are aligned AND the domains are aligned.

Unfortunately, your suggestion does not result in such an output.

[Johannes_B]

Sorry for the late reply, your question somehow got lost within myy stack.

I am not sure if it is possible to align that properly, i would simply suggest to space this by hand. If you have to do this multiple times, this isn't a good solution though.

Code: [Select all] [Expand/Collapse] [Download] (untitled.tex)

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{align}
	a_i &=
	\begin{dcases}
		b_i & i \leq 0 \\
		c_i & i < 0
	\end{dcases} \\
	d_i &= e_i \quad\quad\forall i
\end{align}
\end{document}