[Tex/LaTex] How to typeset a blackboard bold number in amstex

blackboard;plain-tex

I'm using plain TeX with AmsTeX. I can get blackboard bold capital letters, but not numbers. For example, the command \Bbb A prints a capital blackboard bold letter A, but the command \Bbb 1 displays a strange symbol which, of course, is not a blackboard bold number.

Best Answer

The msbm font has only blackboard bold uppercase letters and the lowercase k.

If you want digits, you have to use another blackboard bold font.

Here's the code for bbold

\input amstex
\loadmsbm

\catcode`@=11
\font@\tenbbold=bbold10
\font@\sevenbbold=bbold7
\font@\fivebbold=bbold5
\newfam\bboldfam
\textfont\bboldfam=\tenbbold
\scriptfont\bboldfam=\sevenbbold
\scriptscriptfont\bboldfam=\fivebbold
\def\xbb{\RIfM@\expandafter\xbb@\else
 \expandafter\nonmatherr@\expandafter\xbb\fi}
\def\xbb@#1{{\xbb@@{#1}}}
\def\xbb@@#1{\noaccents@\fam\bboldfam\relax#1}

\catcode`@=\active % @ is active in amstex

$\Bbb{A}\xbb{0123456789}$

\bye

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