What does the following mean:
$\nsubseteq$
I cant find any definition for it?
Previous editor's note: I replaced a linked image with the $\nsubseteq$ symbol to make the question self-contained. I am pointing this out here to avoid comments/questions such as, "You don't know what it means but you know how to write it in $\mathrm\TeX$?"
Best Answer
Quite simply, $\not\subseteq$ means "not subset of." Hence, $A\not\subseteq B$ means that $A$ is not a subset of $B$.
All the more to make this clear, that symbol is easily typeset with
\not\subseteq.