# Command for transverse, and not \pitchfork, as used in Guillemin and Pollack

In Guillemin and Pollack's Differential Topology book, they use the notion of transverse, but not the \pitchfork to denote it. It is very similar, but has a 'T' in it instead of just a ' | ' in the symbol.

The following picture (taken from the book preview in Google Books, page 68) shows the symbol

I and my peers have searched for a convenient way to produce this symbol, but the quick and easy ways produce unsatisfying result, such as \overline and \bar. Before we go and draw one and make a command, I thought I would see if anyone has knowledge of this being available in some package or a better way to get what we want. Thanks.

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Welcome to TeX.SX! I have added an image taken from the preview on Google Books –  egreg Sep 24 '13 at 13:28
this symbol is unicode 2ADA, "pitchfork with tee top". it should be found in the xits or stix fonts; i believe the name assigned is \topfork. –  barbara beeton Sep 24 '13 at 13:55

Here's a way to construct the symbol:

\documentclass{article}
\usepackage{amsmath,amssymb}

\newcommand{\transv}{\mathrel{\text{\tpitchfork}}}
\makeatletter
\newcommand{\tpitchfork}{%
\vbox{
\baselineskip\z@skip
\lineskip-.52ex
\lineskiplimit\maxdimen
\m@th
\ialign{##\crcr\hidewidth\smash{$-$}\hidewidth\crcr$\pitchfork$\crcr}
}%
}
\makeatother

\begin{document}
$f_{s} \transv Z$

$X_{f_{s} \transv Z}$
\end{document}


If you don't plan to use the symbol in sub/superscripts, you may remove the \text around \tpitchfork.

If you'd like to lower the symbol, add something like \raise-0.1ex just before \vbox in the definition of \tpitchfork and adjust the 0.1 to suit.

\newcommand{\tpitchfork}{%
\raise-0.1ex\vbox{
\baselineskip\z@skip
\lineskip-.52ex
\lineskiplimit\maxdimen
\m@th
\ialign{##\crcr\hidewidth\smash{$-$}\hidewidth\crcr$\pitchfork$\crcr}
}%
}

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shouldn't this be centered vertically on the math axis? also, the name \topfork has been assigned in the stix fonts latex support (not yet fully released), so it would be reasonable to keep the same name in order to avoid possible later confusion. –  barbara beeton Sep 24 '13 at 13:58

This package constructs the symbol in \textstyle using the \stackinset macro from stackengine. Then, it uses the \scalerel macro of the package of the same name to scale that construct to the vertical size of a \pitchfork in the current math style. It imports that current math style into the \raisebox by way of the \ThisStyle{...\SavedStyle...} syntax.

\documentclass{article}
\usepackage{amssymb}
\usepackage{stackengine}[2013-09-11]
\usepackage{scalerel}
\stackMath
\def\ptt{\mathrel{\ThisStyle{\raisebox{-.2ex}{$\SavedStyle\scalerel*% {\stackinset{c}{}{t}{.5ex}{\smash{-}}{\pitchfork}}{\pitchfork}$}}}}
\begin{document}
$$A \ptt C_{(A \ptt C)}$$
\end{document}


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