# alignment of equations in align environment with itemize

I am using amsmath environment and I want to align equations with multiple align environment. An example can be seen in the figure:

Now what i want is shown in arrows. I want i=0,..2n in eq 2.4.2 to shift leftwards so this text is aligned with the text of equation 2.4.1. at the same time i also want eq 2.4.3 to be aligned with eq 2.4.2. an example code is given below:

         \documentclass[hidelinks,a4paper,11pt]{report}
\usepackage{amsmath}
\begin{document}

\begin{enumerate}
\item Form $2n+1$ sample points (also known as sigma points) vectors $x^{(i)}$  as follows:
\begin{aligned} x^{(i)}=\begin{cases}\bar{x} & \text{i=0} \\ \bar{x}+\left(\sqrt{(n+\lambda)P}\right)^T_i & \text{i=1,\cdots,n} \\[1.2ex] \bar{x}-\left(\sqrt{(n+\lambda)P}\right)^T_i & \text{i=n+1,\cdots,2n} \end{cases} \end{aligned}
\item Transform sigma points:
\begin{align}
y^{(i)} &= h(x^{(i)}) & \text{$i=0,\cdots,2n$}
\end{align}
\item Approximate mean and covariance as given below:
\begin{align}
{y}_u &=\sum_{i=0}^{2n}W^{(m)}_i y^{(i)}\notag\\
P_u &=\sum_{i=0}^{2n}W^{(c)}_i \left(y^{(i)}-y_u\right)\left(y^{(i)}-y_u\right)^T
\end{align}
\end{enumerate}
\end{document}


Inside different math environments, it is highly impossible to do that alignment. But in the same environment (align here) it is possible with some manual intervention.

\documentclass[a4paper,11pt]{report}
\usepackage{amsmath}
\begin{document}
\noindent Some text follows
\begin{enumerate}
\item Form $2n+1$ sample points (also known as sigma points) vectors $x^{(i)}$  as follows:
\begin{align}
\qquad  x^{(i)}&=\begin{cases}\bar{x} & \text{$i=0$} \\
\bar{x}+\left(\sqrt{(n+\lambda)P}\right)^T_i & \text{$i=1,\cdots,n$} \\[1.2ex]
\bar{x}-\left(\sqrt{(n+\lambda)P}\right)^T_i & \text{$i=n+1,\cdots,2n$}
\end{cases}
%
\intertext{\item Transform sigma points:}
y^{(i)} &= h(x^{(i)}) \hphantom{\left(\sqrt{(n+\lambda)P}\right) y^{(i\,}}  \text{$i=0,\cdots,2n$}
%
\intertext{\item Approximate mean and covariance as given below:}
{y}_u &=\sum_{i=0}^{2n}W^{(m)}_i y^{(i)}\notag\\
P_u &=\sum_{i=0}^{2n}W^{(c)}_i \left(y^{(i)}-y_u\right)\left(y^{(i)}-y_u\right)^T
\end{align}
\end{enumerate}
\end{document}


I have used \quad in the beginning of first equation and \hphantom for some alignment. The equations are not guaranteed to be centred. If your equations go beyond a page break, you may add \allowdisplaybreaks in the preamble.

• Thanks ! It works, I guess it is not a good idea to use different math environments in this scenario. It was a bit tricky to solve this...
– Umz
Nov 28, 2013 at 3:08
• @Umz Glad it helped :-)
– user11232
Nov 28, 2013 at 3:09
• It looks so wrong to me that the other \items are nested within the math environment... but even within beamer and several \uncover commands, this solution works flawlessly!
– ojdo
Nov 29, 2016 at 15:07