How to do a bold 1 (\mathbbm{1}) in MathJax

Question

I'm looking for blackboard bold numerals in LaTeX displayed with MathJax. It seems that the \mathbbm command is not (yet) available from MathJax (as said in the documentation).

Is there anyway to have support for the \mathbbm command, e.g., to have nice bold 1 ? I tried to load an extension, or trick from this question, but nothing works.

Here is an example showing the failure: with makebigmaths.

It seems to be a known and old issue of MathJax, coming from a font limitation. And no third party extensions seem to solve it.

However, Jupyter notebooks supports it in its Markdown cells.

Dree

You might want to clarify that you're after blackboard bold numerals. – Meeting

Answer 1

You can use Unicode characters directly, e.g., 𝟙, or via the non-standard macro \unicode{x1D7D9}.

Both of these can be used in macro definitions as well, cf. http://docs.mathjax.org/en/latest/tex.html#defining-tex-macros.

Meeting

Answer 2

One can use \Bbb instead of \mathbbm which is mentioned under "Font control" in the current documentation. Judging by the question Obsolete command \Bbb, it is an obsolete TeX command.

I use \Bbb in an align environment using MathJax version 3.2.2 for doxygen.

Tsingyuan