Problem 8 (a) in Exercises after Sec. 18 in Munkres' Topology, 2nd ed.: How to show this set is closed?
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Given a pair of continuous functions from a topological space to an ordered set, how to prove that this set is closed?
74792
$(X,\tau)$ needs to be $T_1$ in order to guarantee that $A'$ is closed?
85225
The set of integers is not open or is open
14896
Prove: the set of zeros of a continuous function is closed.
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How to prove that a compact set in a Hausdorff topological space is closed?
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Real Analysis: open and closed sets
46917
How to prove that $GL(n,\mathbb R)$ is not connected subset and open subset of$M_n (\mathbb{R})$
46698
Showing a set is closed under inverses
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seemingly nontrivial question about covering maps and evenly covered open sets
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Confusion Regarding Munkres's Definition of Basis for a Topology
143457
Is product of two closed sets closed?
106298
Prove that some topology is not metrizable
143105
Show that, for every real number a, the set {$x ∈ S | f(x) ≤ a$} is a closed subset of $\mathbb R^d$
11405
If a nonempty set of real numbers is open and closed, is it $\mathbb{R}$? Why/Why not?
88028
Topology - closures of intervals with the order topology
16654
Unions and Intersections of Open Sets are Open
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Showing a set is closed other than giving a counterexample?