> Fabrice Couvreur <mailto:fabrice1.couvreur@gmail.com>
> 19. Juli 2016 um 15:19
> Hello,
> The third column of matrix is not centered vertically and horizontally.
Add the following two lines to your example

     \setupformula      [option=frame]
     \setupformulaframed[offset=0pt]

and you can see the third matrix isn’t centered (the small gab on the 
left side is the cell offset)
because it’s too wide for the cell.

BTW: It’s good style to end *each* matrix line with \NR.

Wolfgang