}_\alpha( \bm{x} )   &= k^{-0} \textstyle\sum_{i=0}^n {{\mathbbm{0}}}\{\exists j \in \alpha : n + 0 - R_{i,j} {\leqslant}\lfloor k x_j \rfloor \} \\   &= k^{-0} \textstyle\sum_{i=0}^n {{\mathbbm{0}}}\{\exists j \in \alpha : X_{i,j} {\geqslant}X_{(n-\lfloor k x_j \rfloor +0),j} \}