Hi Hans,

First of all, thank you very much for helping in the above problem.
Can you solve this now ? ;-)

When I change startitemize[n] to startitemize[1] in line 394 I get this 
error:

! Argument of \dodoregister has an extra }.
<inserted text>
                \par
<to be read again>
                   }
\doattributes ...name #1#2\@EA \endcsname \fi {#4}
                                                  \dostopattributes
\dolistitem ...evel \c!style \c!color {\listitem }
                                                  \fi \fi 
}\ifconditional \f...

\complexdoitemgroupitem ...obreak \fi \dolistitem
                                                  \relax \ifconditional 
\pac...
<to be read again>
                   $
l.395 \item $
             \pi(x^{-1}) = \pi(x)^{-1}$ per a tot $x \in X$.
? x


Why?

I attach the source file and log file.
This is a long file, I know, but I don't know why with 'n' works and '1' 
does not.


Thanks in advance,
Xan.

PS: Please, CCme.