 reserve X,Y,Z,E,F,G,S,T for RealLinearSpace;
 reserve X,Y,Z,E,F,G for RealNormSpace;
 reserve S,T for RealNormSpace-Sequence;

theorem
  for X,Y being RealNormSpace-Sequence,
        Z being RealNormSpace
  ex I be LinearOperator of R_NormSpace_of_BoundedLinearOperators
    (product X,R_NormSpace_of_BoundedLinearOperators(product Y,Z)),
    R_NormSpace_of_BoundedMultilinearOperators(<*product X,product Y*>,Z)
  st I is bijective isometric
   & for u be Point of R_NormSpace_of_BoundedLinearOperators
      (product X,R_NormSpace_of_BoundedLinearOperators(product Y,Z ))
     holds ||.u.|| = ||. I.u .||
   & for x be Point of product X,y be Point of product Y
     holds (I.u).<*x,y*> = (u.x).y by IS04A;
