Fonts & Character Sets ⇒ Blackboard bold numbers; trouble with \mathbb

[299792458]

Hello everyone,

I just started using LaTeX and I have an issue with the \mathbb command. Letters work just fine, but when I am trying to use double-struck numbers, e.g. with \mathbb{1}, this character

character.jpg (631 Bytes) Viewed 35381 times

shows up instead of the blackboard bold number 1. I did find out I can circumvent this by creating combining the characters "1" and "I" to make somewhat of a double-struck "1", but I would still like to know what is going wrong when I use \mathbb.

Any help would be appreciated.

[Stefan Kottwitz]

Welcome to the board!

\mathbb (of amsfonts) supports only letters, not digits. You could use bbm:

Code: Select all

\documentclass{article}
\usepackage{bbm}
\begin{document}
\[
  \mathbbm{1}
\]
\end{document}

identity-bbm.png (433 Bytes) Viewed 35381 times

Or dsfont:

Code: Select all

\documentclass{article}
\usepackage{dsfont}
\begin{document}
\[
  \mathds{1}
\]
\end{document}

identity-ds.png (876 Bytes) Viewed 35381 times

Stefan

[299792458]

Thanks for the quick response.

I have a follow-up beginner's question right away: Is there an easier way of installing dsfont in MiKTeX than figuring out by myself where to put the individual files, as the documentation suggests? As it appears to me the dsfont package cannot be installed via the package manager in MiKTeX.

[localghost]

[…] I have a follow-up beginner's question right away: Is there an easier way of installing dsfont in MiKTeX than figuring out by myself where to put the individual files, as the documentation suggests? As it appears to me the dsfont package cannot be installed via the package manager in MiKTeX.

Search the package list in the MiKTeX Package Manager (MPM) for the doublestroke package and install it.


Thorsten