# Is there a better (more condensed) way of formatting a subscript \perp (or \bot)?

I'm writing a lot of these types of formulas:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$$\mathrm{e}^{-\mathrm{i} \boldsymbol k_\bot \cdot \boldsymbol r_\bot}$$
\end{document}


In which the perpendicular symbol takes quite some space, which makes the equation less readable. Is there a simple way to either do this better, or make the \perp symbol smaller for this case? The less hackish the better, but I understand this is latex :-)

• I know what B.S. is, but what is \bs? – Steven B. Segletes Jun 3 '14 at 12:42
• @StevenB.Segletes: \bs = \boldsymbol ? (At least it is my short macro for that ;-)) – user31729 Jun 3 '14 at 12:42
• Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – user31729 Jun 3 '14 at 12:43
• use a \! after the \bot for a small backspace. – Steven B. Segletes Jun 3 '14 at 12:44
• @rubenvb: Perhaps \perp might help – user31729 Jun 3 '14 at 12:44

Here, I really squeeze it with a \! to the left of the \bot and two to the right. As a less intense version, a single \! to the right would do.

\documentclass{article}
\usepackage{amsmath}
\def\mybot{{\!\bot\!\!}}
\begin{document}
$$\mathrm{e}^{-\mathrm{i} \boldsymbol k_\mybot \cdot \boldsymbol r_\mybot}$$
\end{document}


Here is the less intense version:

\documentclass{article}
\usepackage{amsmath}
\def\mybot{{\bot\!}}
\begin{document}
$$\mathrm{e}^{-\mathrm{i} \boldsymbol k_\mybot \cdot \boldsymbol r_\mybot}$$
\end{document}


And, taking Heiko's suggestion, which carries great weight on this site, of placing a single \! on either side of the \bot produces the following:

\documentclass{article}
\usepackage{amsmath}
\def\mybot{{\!\bot\!}}
\begin{document}
$$\mathrm{e}^{-\mathrm{i} \boldsymbol k_\mybot \cdot \boldsymbol r_\mybot}$$
\end{document}


• \cdot is a binary operator; I do not think, it should be too close to the left operand, thus I prefer one \! on both sides each. – Heiko Oberdiek Jun 3 '14 at 13:07
\documentclass{article}
\usepackage{amsmath,bm}
\def\Bot{\scriptscriptstyle\kern-1pt\bot\kern-1pt}

\begin{document}
$$\mathrm{e}^{-\mathrm{i} \bm k_{\Bot}\!\cdot \bm r_{\Bot}}$$
\end{document}