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5.4 The Cofactors of the Matsuno Determinant  197

                     =    E ii  (c r + c s )E  rs
                             r,s
                        i

                     =2    E  ii  c r E ,                           (5.4.30)
                                     rr
                         i     r

                  G =2     c r E E .                                (5.4.31)
                               ir
                                  rj
                        i,j,r
          Modify (5.4.10) with j = i by making the changes i ↔ r and s → j. This
          gives

                                G =2    c r   E E .                 (5.4.32)
                                               ir
                                                  ri
                                      r
                                            i
          Hence,

                              2   2                E ii  E  ir
                            (c − c )E ij  =2
                                                 E    E  rr
                              i   j           c r    ri
                          i,j              i,r

                                       =2     E ir,ir ,
                                           i,r
          which is equivalent to (5.4.22).
            To prove (5.4.23) multiply (5.4.10) by (c i −c j ), sum over i and j, change
          the dummy variables as indicated, and refer to (5.4.6):
                                         2
                                  (c i − c j ) E  ij  = H − J,      (5.4.33)
                               i,j
          where

                 H =    (c i − c j )  E E rj
                                    is
                      i,j       r,s
                                                               
                                                  
                                                               
                   =     E  rj     c i E  is   −    E  is   c j E  rj 
                             
                                                     
                                                               
                       r,j       i,s           i,s       r,j
                                (s→j)                   (r→i)

                   =    E rr   (c i − c j )E ,                      (5.4.34)
                                       ij
                      r     i,j

                 J =    (c i − c j )  E E .                         (5.4.35)
                                    ir
                                       rj
                                 r
                      i,j
          Hence, referring to (5.4.20) with suitable changes in the dummy variables,

                                 2                   E  ij  E  ir
                          (c i − c j ) E  ij  =  (c i − c j )
                                                    E rj  E  rr
                        i,j             i,j,r

                                     =     (c i − c j )E  ir,jr
                                        i,j,r
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