Prove: a closed ball is a closed set
35573
A closed ball in a metric space is a closed set
778
For $x∈\mathbb{R}^n$ , let $B(x,r)$ denote the closed ball in $\mathbb{R}^n$(with Euclidean norm) of radius $r$ centered at $x$
147247
Continuous function on closed unit ball
13848
Showing that if a subset of a complete metric space is closed, it is also complete
3649
Closed unit interval is connected proof
128482
The set of subsequential limits is closed
153495
Continuous function does not map closed set to closed set
78117
Closed property of nonempty finite set
158155
Is set of isolated points of S closed?
32534
Prove that a set $S \subseteq \mathbb{R}$ is closed and bounded if and only if every sequence in $S$ has a sub sequence converging to a point of $S$.
86317
Show that $F\subset Y$ is closed in $Y$ iff $F=Y\;\cap\;H$ where $H\subset X$ is closed in $X$.
143105
Show that, for every real number a, the set {$x ∈ S | f(x) ≤ a$} is a closed subset of $\mathbb R^d$
44623
Closed set as a countable intersection of open sets
70959
Prove that a set $E$ is closed iff it's complement $E^{c}$ is open
95244
Prove that a finite union of closed sets is also closed
33310
Proving that the set of limit points of a set is closed
125962
The set $A'$ is closed in a $T_1$ space