The *correct* way to typeset optimization problems in LaTeX

opt.tex

% Output: http://i.imgur.com/88G3s9V.png
\begin{equation}
  \begin{split}
                 & \text{\large Primal} \\
    \text{min }  & \sum_{j=1}^s x_j + Bz \\
    \text{s.t. } &
    \begin{aligned}[t]
      x_j + z &\ge 1 & \forall j = 1,2,\dots,s \\
          x_j &\ge 0 & \forall j = 1,2,\dots,s \\
            z &\ge 0
    \end{aligned}
  \end{split}
  \qquad
  \begin{split}
                 & \text{\large Dual} \\
    \text{max }  & \sum_{j=1}^s y_j \\
    \text{s.t. } &
    \begin{aligned}[t]
                     y_j &\le 1 & \forall j = 1,2,\dots,s \\
      \Sigma_{j=1}^s y_j &\le B \\
                     y_j &\ge 0 &\forall j = 1,2,\dots,s
    \end{aligned}
  \end{split}
\end{equation}