>>> "Eric" == Eric S Fraga <esflists@gmail.com> writes:

   > On Friday, 15 Jun 2018 at 10:52, Uwe Brauer wrote:
   >> Both a set to nil, but even if I try dvipng via 
   >> 
   >> #+OPTIONS: tex:dvipng
   >> 
   >> Or           #+OPTIONS: tex:imagemagick

   > Data point:

   > Both work for me.  The dvipng output looks better, however.  The mathml
   > doesn't work (for me) for the second case with the align environment.

   >> The math, even equations are inserted verbatim, that is really odd.
   >> The minibuffer tells me that the png are generated and indeed there are,
   >> but they are not inserted in the odt file using as  org-export-dispatch
   >> and then chosing odt.

   > Strange.  Cannot help.  Sorry.

Ok I found the culprit, I debugged ox-odt.el
it is the following function 


(defun org-odt-format-headline-default-function
     (let* ((style (format "OrgPriority-%s" priority))
                                     ^^^^^ this is the problem.

The new code has 

  (let* ((style (format "OrgPriority-%c" priority))

And this solves the eqnarray problem. Good, uff relived. Now I can go
home ;-)