I'd like to have a symbol that is the exact overlap between \top and \bot so that it looks like the roman number "Ⅰ". I have searched a particular symbol, but I found nothing. And overlapping techniques in this and other forums are a little confusing.

Can someone help me?

  • 2
    One very simple alternative: a similar-looking character in Unicode, which you could use with unicode-math, is U+2336, APL functional symbol I-beam(⌶). The accepted answer is great, though.
    – Davislor
    Commented Feb 11, 2018 at 21:37

2 Answers 2


The following code implements \bottop that combines \bot and \top with respecting the current math style:


  % #1: math style
  % #2: unused
  \rlap{$#1\bot\m@th$}% put \bot to the right without moving the current point

\[ \bottop \scriptstyle \bottop \scriptscriptstyle \bottop \]



From http://tug.ctan.org/info/symbols/comprehensive/symbols-a4.pdf here is a possible implementation:


\def\topbotatom#1{\hbox{\hbox to 0pt{$#1\bot$\hss}$#1\top$}}

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