Missing $ inserted in a logic function

Such commands like \neq etc. need math mode, i.e. switching into that mode with $...$ or \( ...\).

'Care' must be taken when hyperref is used in conjunction with math mode within arguments of structuring commands like \section, \subsection, etc, of course \paragraph too, if this is to be included into the bookmarks and ToC.

\documentclass{article} \usepackage{mathtools} \setcounter{secnumdepth}{4} \setcounter{tocdepth}{4} \begin{document} \tableofcontents \section{First} \subsection{First} \subsubsection{First} \paragraph{ $\neg A \wedge (B \vee C)$ } \end{document}