On 2016-08-16 15:20, Uwe Brauer wrote:
> Hello
> 
> It seems to me mostly a question for GNU emacs, but I put the
> auctex-devel list on the CC just in case.
> 
> When I compile a LaTeX document which contains.
> 
> $\phi \varphi$
> 
> The pdf file presents these symbols as  (screenshot attached)
>  ϕ φ
> 
> 
> But when I use prettifying \varphi is not displayed and \phi is
> displayed as if it were \varphi
> 
> On top of that when use set-input-method TeX
> 
> And
> 
> \phi --> φ
> 
> \varphi --> ϕ 
> 
> So it seems to me, latex is right input-method is wrong and prettifying
> as well.
> 
> Any comments

The input method and prettification both take the "pragmatic" decision of rendering \phi as GREEK SMALL LETTER PHI instead of GREEK PHI SYMBOL, presumably because it has better font support or because of consistency with the rest of the greek alphabet.

Some extra data points:

* The unicode-math package translates GREEK PHI SYMBOL to \phi, and GREEK SMALL LETTER PHI to \varphi, so the input method is inconsistent with unicode-math.

* The company-math package translates \phi to GREEK PHI SYMBOL and \varphi to GREEK SMALL LETTER PHI, consistently with your expectations.

Clément.