Closedness of a mapping $p : [0,1] \cup [2,3] \to [0,2]$
52629
Example 1, Sec. 22 in Munkres' TOPOLOGY, 2nd edition: How to verify that this map is closed?
134575
Show that the mapping $f → f~'$ from $C^1([0 , 1])$ to $C([0 , 1])$ is not continuous.
95244
Prove that a finite union of closed sets is also closed
55764
Algebraic closure of $\mathbb F_p$
21114
$S=\{(n,{1\over n}):n\in\mathbb{N}\}$ is closed in $X$?
150166
What is $P([a_1,b_1]\times [a_2,b_2]\times...\times[a_k,b_k])$
143457
Is product of two closed sets closed?
52323
Maps - question about $f(A \cup B)=f(A) \cup f(B)$ and $ f(A \cap B)=f(A) \cap f(B)$
24050
Characterization of the Closure of a Set
74792
$(X,\tau)$ needs to be $T_1$ in order to guarantee that $A'$ is closed?
10477
Finding the closure of A=$\mathbb Q \cap [0,1]$.
121095
Is convex hull of a finite set of points in $\mathbb R^2$ closed?
36315
Is $[0,1]$ a countable disjoint union of closed sets?
143586
Is $[0,1]$ a union of family of disjoint closed intervals?
28683
Sum of two closed sets in $\mathbb R$ is closed?
23239
Prove that the following map has at least $k-2$ fixed points
115376
Is $(-\infty,3]\cap(0,1)^c\cap[-1,\infty)$ closed? Open? What are interior points?