I know the identity $\operatorname{int}(C \cup D) \supset \operatorname{int}(C) \cup \operatorname{int}(D) $.
I need to find a counterexample showing that equality does not hold in general.
Could you please give me any hint?
2025-01-12 22:10:31.1736719831
Counterexample to show that the interior of union may be larger than the union of interiors
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