[Tex/LaTex] Dynamically size arrow \mapsto in function definition

horizontal alignmentmath-modesymbols

I have the following diagram:


However, this looks a bit ugly, I would like a version that looks a little bit better. For example, size the last arrow such that the T_\phi is moved to the right.

This is the code which I am using to do this:

  \xi \colon &\lb \to \mathcal{L}(\hh)\\
  &\phi \mapsto T_\phi.

Where \lb and \hh just give the names for those spaces. Does anybody have a suggestion how I would improve the look of this function definition?

Best Answer

Personaly, I think it is better to use:

enter image description here

  \xi \colon L^\infty(T) &\to \mathcal{L}(H^2)\\
  \phi &\mapsto T_\phi.

Anyway, you can obtain what you want through



  \setbox0=\hbox{$\displaystyle #1\to$}%
  \hbox to \wd0{%


  \xi \colon &L^\infty(T) \to \mathcal{L}(H^2)\\
  &\phantomarrow{L^\infty(T)}{\phi} T_\phi.


enter image description here