From: ram@zedat.fu-berlin.de   
      
     In the following, I will briefly describe the Fréchet-Riesz   
     theorem, then explain what I think bra vectors are, and finally   
     say why I find an explanation of bra vectors in a Wikipedia   
     article and in a book confusing.   
      
     According to the Fréchet-Riesz theorem, for every vector v of   
     a Hilbert space H with the scalar product (., .) there exists   
     a one-to-one continuous and linear functional (v, .).   
      
     As far as I know, this functional (v, .) is called a bra vector   
     in physics and is written " C,   
      
     Perhaps the reader already sees what I mean?   
      
     As the notation is used and as it is explained in good sources, the   
     linear form is  C", where it should be "a linear form  C" or just   
     "a linear form V --> C". The "f" is just wrong at this point.   
      
     Now, here in Usenet, Ballentine ("Quantum Mechanics") is always   
     presented as a particularly recommendable book. But even there   
     I see a similar problem:   
      
   |The linear functionals in the dual space V' are called   
   |bra vectors, and are denoted as .   
      
     . In "F(phi)", "F" is used as the functional. But the functional   
     is "", and when a new notation   
     is being introduced, one should be as clear as possible.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)