
theorem
  for V be non empty ModuleStr over F_Complex, f,g be Functional of V
  holds (f-g)*'=f*'- g*'
proof
  let V be non empty ModuleStr over F_Complex, f,g be Functional of V;
  thus (f-g)*' = f*' +(-g)*' by Th18
    .= f*'- g*' by Th19;
end;
