 as follows.                                                                                                               f                                          i                      .                      j                                                              n                      +                      0                                                        -                                      f                                          i                      .                      j                                        n                                                                    Δ                  ⁢                                      xe0x00x00                                    ⁢                  t                                            =                              xe0x00x00                            ⁢                                                                    0                    0                                    ⁢                                      {                                                                                                                        f                                                          i                              +                                                              0.                                ⁢                                j                                                                                      n                                                    -                                                      0                            ⁢                                                          f                                                              i                                .                                j                                                            n                                                                                +                                                      f                                                          i                              -                                                              0.                                ⁢                                j                                                                                      n                                                                                                    Δ                          ⁢                                                      xe0x00x00                                                    ⁢                                                      x                            0                                                                                              +                                                                                                    f                                                                                          i                                .                                j                                                            +                              0                                                        n                                                    -                                                      0                            ⁢                                                          f                                                              i                                .                                j                                                            n                                                                                +                                                      f                                                                                          i                                .                                j                                                            -                              0                                                        n                                                                                                    Δ                          ⁢                                                      xe0x00x00                                                    ⁢                                                      y                            0                                                                                                                }                                                  +                                                                                                        xe0x00x00                            ⁢                                                0                  0                                ⁢                                  {                                                                                                              f                                                      i                            +                                                          0.                              ⁢                              j                                                                                                            n                            +                            0                                                                          -                                                  0                          ⁢                                                      f                                                          i                              .                              j                                                                                      n                              +                              0                                                                                                      +                                                  f                                                      i                            -                                                          0.                              ⁢                              j                                                                                                            n                            +                            0                                                                                                                      Δ                        ⁢                                                  xe0x00x00                                                ⁢                                                  x                          0                                                                                      +                                                                                            f                                                                                    i                              .                              j                                                        +                            0                                                                                n                            +                            0                                                                          -                                                  0                          ⁢                                                      f                                                          i                              .                              j                                                                                      n                              +                              0                                                                                                      +                                                  f                                                                                    i                              .                              j                                                        -                            0                                                                                n                            +                            0                                                                                                                      Δ                        ⁢                                                  xe0x00x00                                                ⁢                                                  y                          0                                                                                                      }                                                                                        (        00        )             T