I am looking for a 'blackboard-bold' style comma notation. In particular, is there a comma similar to the lower part in \fatsemi from the stmaryrd package? I tried to search 'fat comma', 'blackboard-bold comma', but did not get anything wanted. I am aware of using the approach similar to \fcmp but that looks less nice to me.

  • 1
    Welcome to TeX.SE! Can you show us a short compilble TeX code?
    – Mensch
    Commented Nov 21, 2022 at 17:53
  • The bbold font has one. Commented Nov 21, 2022 at 18:09

2 Answers 2


You can grab the glyph from the bbold font. The style is a little bit different from that of \fatsemi though:

\usepackage{stmaryrd, bbold}


        \verb|\fatsemi|:        & $a\fatsemi b$ \\
        \verb|bbold| semicolon: & $a\bbsemicolon b$ \\ 
        \verb|bbold| comma:     & $a\bbcomma b$ \\ 

enter image description here


You could use trimclip:

enter image description here


\usepackage{stmaryrd, trimclip}

\newcommand{\fatcomma}{\mathbin{\clipbox*{0 -1ex {\width} .66ex}{$\fatsemi$}}}


$a\fatsemi b$

$a\fatcomma b$


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