# A problem typing (') in LaTeX

What is this? I'm just trying to write '

Entry:

Output:

My code:

\documentclass[a4paper]{article}
\usepackage[margin=1.5cm]{geometry}
\usepackage{helvet}
\renewcommand\familydefault{\sfdefault}
\usepackage{mathastext}
\usepackage[most]{tcolorbox}
\usepackage{pgfplots,relsize}
\usepgfplotslibrary{fillbetween}

\def\h {1.3ex} % cup and cap height
\def\w {1.2ex} % cup and cap width
\def\lw{0.12ex} % cup and cap line width
\def\sp{0.7269ex} % space before and after
\newcommand{\mysymbol}[1]
{
\hspace{\sp}
\tikz[line width=\lw,line cap=round,rotate=#1,baseline=-0.4ex]   {\draw (-0.5*\w,0.5*\h) -- (-0.5*\w,0.5*\w-0.5*\h) arc (-180:0:0.5*\w) -- (0.5*\w,0.5*\h);}
\hspace{\sp}
}
\newcommand{\mycup}{\mysymbol{0}}
\newcommand{\mycap}{\mysymbol{180}}
\newcommand{\mysub}{\mysymbol{270}}
\newcommand{\mysup}{\mysymbol{-360}}

\begin{document}

\begin{align*}
p' \wedge q
\end{align*}

\end{document}

• Can you give a bit of context, i.e., the code of the document that shows this behavior? It is definitely not normal, \documentclass{article} \begin{document} $\wedge(q' \wedge r)$ \end{document} compiles without problems. Sep 19, 2021 at 18:56
• Please show the couple of lines of code -- preferably the code itself, not a screen shot of code -- that precede the one you've chosen to show.
– Mico
Sep 19, 2021 at 18:56
• Don't ever redefine \sp -- or, for that matter, \sb -- unless you want to come to grief. (Hint: \sp and \sp are short for superscript and subscript.)
– Mico
Sep 19, 2021 at 19:34
• Basically the problem is using \def (which is not LaTeX) - using \newcommandwould have triggered a redefinition error. It's a good habit to use it especially for short macro names, where clashes are more probable. Sep 19, 2021 at 20:25
• You've already received an answer, but here's a good tip* for troubleshooting: look at what is bring printed and compare it with your preamble definitions. "0.7269ex" is a slightly random thing to be bring printed. You should then check your definitions---which, as others have said, should use \newcommand not \def---to see if this appears anywhere. This method doesn't find the culprit every time, and it certainly doesn't give the full answer given below, but it can help diagnose the issue. [*I feel that it's a good tip; it works well for me, at least!] Sep 20, 2021 at 8:25

The problem is occurs with the package mathastext and your definition of \sp. It seems like mathastext uses \sp in its definition of ':
\def\mst@active@math@prime{\sp\bgroup\mskip\mst@prime@muskip\prim@s}