\[
  \begin{array}{r l l}
    \RktMeta{\++} & = & \lambda\,\vectorgen{v_0~v_1}\,.\,
                          \left\{\begin{array}{l l}
                            \vectorgen{v_{00}, \ldots, v_{0m}, v_{10}, \ldots, v_{1n}}
                            & \RktMeta{if}~v_0 = \vectorgen{v_{00}, \ldots, v_{0m}}
                              ~\RktMeta{and}~v_1 = \vectorgen{v_{10}, \ldots, v_{1n}}
                          \\\bot & \RktMeta{otherwise}
                          \end{array}\right.
  \end{array}
\]