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A negated relation symbol indicating that one set is not a subset of another set in set theory.

$\nsubseteq image$

Examples

\{1, 2, 3\} \nsubseteq \{1, 2\}

\{1, 2, 3\} \nsubseteq \{1, 2\}

\mathbb{R} \nsubseteq \mathbb{Q} \cup \{\pi\}

\mathbb{R} \nsubseteq \mathbb{Q} \cup \{\pi\}

V_1 \nsubseteq W \text{ since } v \in V_1 \text{ but } v \notin W

V_1 \nsubseteq W \text{ since } v \in V_1 \text{ but } v \notin W