# [NTG-context] Math blackboard (bug?)

Hans Hagen j.hagen at xs4all.nl
Sat Jan 9 18:09:46 CET 2021

```On 1/9/2021 1:31 PM, Johann Birnick wrote:
> To write blackboard math, the syntax was
>
> \$\blackboard{N}\$
>
> , but now this also makes the rest of the text blackboard. So one has to use
>
> \${\blackboard N}\$
>
> . Is this indented? (the old way is a bit easier to use)
>
> Secondly, I want to address the blackboard font. Try out
>
> \starttext
> \${\blackboard NR}\$
> \stoptext
>
> This looks different then in the past. It doesn't have serifs. It looks like the
> wrong font, like sans. Is this a bug? To me it looks awful, honestly. It doesn't
> fit the rest of the math font at all.
Basically we're talking alphabets here and in opentype math fonts these
are complete alphabets. So, \blackboard is an alphabet switch. You can
use \mathbb{X} as an argument variant.

About the shapes ... those are the ones that come with the font (and imo
when blackboard is indeed that what gets drawn on blackboard serifs
probaby make not that much sense, but that's personal).

Hans

-----------------------------------------------------------------