> Hans Åberg <mailto:haberg-1@telia.com>
> 29. Mai 2016 um 18:38
> For some reason, the use of \NN as in the first table below is not 
> working. It works fine using math columns, though, as in the second 
> table below.
What do you expect?

You use in your table math characters which aren’t available in the text 
font and as a result nothing is shown.

Wolfgang