What is the not subset symbol [duplicate]

Question

Possible Duplicate:
How to look up a math symbol?

I am looking for the "not subset" symbol I see in my maths textbook. Wheres that?

In Lyx, I dont see it ... Same here under relations

Answer 1

As always, Detexify is a great help here, or even the Comprehensive LaTeX Symbol List. You are looking for \not\subset:

B \not\subset A

Answer 2

You can use \not\subset, or \not\subseteq, or \nsubseteq (requires the amssymb package):

\documentclass{article}
\usepackage{amssymb}

\begin{document}

\[ A \not\subset B\qquad A \nsubseteq B\qquad A \not\subseteq B \]

\end{document}

The question How to look up a symbol or identify a math symbol or character? could be helpful for you in a similar situation.

Answer 3

Simply use $B \not \subset A$:

\not can create negations of many relations. =)