inserting a right brace within already-aligned equations

Question

My question is quite similar to a previous question on inserting a right brace around a set of equations. However, I do not wish to wrap the brace around the entire aligned environment yet I would like to maintain the same alignment throughout.

I would like to avoid a tikz-based solution if possible.

Any help would be appreciated.

Edit: This example demonstrates that I lose the alignment I would like once I attempt to span some of the equations with a right brace.

\documentclass{beamer}
\usepackage{amsmath}
\begin{document}
\begin{frame} \frametitle{An ILP Approach}
A 0-1 model:
\begin{align*}
  \onslide<2->{
  \mathrm{maximize} \quad & \sum_{e \in E} w_e y_e  \\
  }
  \onslide<3->{
  \text{subject to} & \\
  \left.\begin{aligned}
  x_{il} + x_{jl} + y_e &\leq 2 \\
  x_{il} - x_{jl} &\leq  y_e  \\
  x_{jl} - x_{il} &\leq  y_e  \\
\end{aligned}\right\} \text{for} e \in E, l \in [k]\\
  }
  \onslide<4->{
  \sum_{l \in [k]} x_{il} & = 1 & i \in V \\
  }
  x_{ul}&\in \{0,1\} &\quad \forall u \in V, l \in [k] \\
  y_e &\in \{0,1\} &e \in E
\end{align*}
\end{frame}

\end{document}

Answer 1

Edit: It seems that you looking for the following (showed is only last slide):

\documentclass{beamer}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing,
                calligraphy,
                tikzmark}
\tikzset{
B/.style = {decorate,
            decoration={calligraphic brace, amplitude=4pt,
            raise=1pt},
            thick,
            pen colour=black}
        }

\begin{document}
\begin{frame}
\frametitle{An ILP Approach}
A 0-1 model:
    \begin{align*}
\uncover<2->{
  \mathrm{maximize} \quad & \sum\limits_{e \in E} w_e y_e\\[2ex] 
            } 
\uncover<3->{
  \text{subject to} \quad &         \\
  x_{il} + x_{jl} + y_e &\leq \tikzmarknode{A}{2}     \\
  x_{il} - x_{jl}       &\leq  y_e  \\
  x_{jl} - x_{il}       &\leq  \tikzmarknode{B}{y_e}  \\[2ex] 
            }
\uncover<4->{
\sum\limits_{l \in [k]} x_{il} & = 1  \text{ for } i \in V  \\
            }
                x_{ul}  & \in \{0,1\}, \quad \forall u \in V, l \in [k] \\
                y_e     & \in \{0,1\}, \quad  e \in E
\begin{tikzpicture}[overlay, remember picture]
\draw[B]   (A.north -| B.east) --
    node[right=3mm] {$e \in E, l \in [k]$}
           (B.south east);
\end{tikzpicture}
\end{align*}
\end{frame}
\end{document}

Note: in comparison to your MWE observe that now the aligned environment is removed, right curly braces is drawn by help of tikz package and its library tikzmark and in MWE is only one ampersand per row. Hopeful they are now correct positioning (before math symbols to which you like to have aligned your equations). Also instead of onslide is used \uncover macro.

Showed result appear after two compilation.