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 $\mathrm\TeX$?"
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$\begingroup$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.
Is not a subset of. If $A \nsubseteq B$, it means that $A$ is not a subset of $B$.
$\endgroup$ 2 $\begingroup$If A ⊈ B, then no member of A is a member of B.
The symbol '⊈' represent the negation of the relation of improper inclusion, '⊆'. A ⊆ B if and only if all member of A is a member of B or if A = B.
Must be distinguished from the negation of the proper inclusion '⊂'. 'A ⊂ B' says that all member of A are members of B, but is not the case that A = B.
Thereby, for example, A ⊆ A, but is not the case that A ⊂ A.
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