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Unit 7: Algebra of Linear Transformation




          If U is a linear transformation from V into W with U  =  , i = 1, 2, ... n, then for the vector   =  Notes
                                                     i   i
           n
             x
              i  i , we have
           i  1
                         n
                  U   U    x i  i
                         i  1
                       n
                         x  (U  )
                          i   i
                      i  1
                       n
                         x i i
                      i  1
          So that U is exactly the rule T which we defined above. This shows that the linear transformation
          T with T  =   is unique.
                  i  i
          Relations and operations of Linear Transformations
          1.   Two linear transformations T  and T  from v to w are said to be equal if and only if
                                       1    2
                                         T 1  T 2  for all  . v
          2.   The sum T     T  of linear transformation from v to w are defined, respectively, by
                        1    2
                                    T 1  T 2  )  T 1  T 2  for all  . v
          3.   The scalar multiple C    T  of linear transformations from v to w are defined as
                                     1
                                    c  T 1 ) c T 1 ), for all  , v c F .
                                            (
          Special Linear Transformation
          (a)  The zero linear transformation Z is defined from v to w by

                                        Z =  for every    v
          (b)  Negative transformation (–T) from v to w, is defined by
                                      (–T) = – T for every    v
          (c)  Identity linear transformation I from v to v is defined by
                                         I =   for every    v

          (d)  Product transformation T   T .
                                   1   2
          Let v, w and y be vector spaces over the field F; let T  be a linear transformation from v to w and
                                                    1
          T  be a linear  transformation from  w to  y. Then the  product transformation  T    T   is  the
           2                                                                1    2
          mapping from v to y defined by
                  (T   T ) = ( T )T  for every     v.
                    1   2     1  2
          Thus for every T we have

                 T   Z = T
                 T   –T = Z
                 T  I = I  T + T.









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