[Tex/LaTex] Symbol for not an ideal

Question

I'm trying to write the symbol for not an ideal.
I've been using \lhd to represent an ideal so what I want is to put a line through this in the same way \neq or \nless do for \eq and \less.

Any suggestions?

Answer 1

Use \centernot from the same package.

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

\begin{document}

$\centernot{\lhd}$

\end{document}