: include_once(../../../../../site/defns.php): Failed to open stream: No such file or directory in
: include_once(): Failed opening '../../../../../site/defns.php' for inclusion (include_path='.:/usr/share/php') in
Let $(\mathcal M, d)$ be a metric space.
-
Suppose $E \subseteq M$, and $x \in E$ is not a cluster point of $E$.
Then the statement "$x$ is an interior point of $E$"...
- ...is always true.
- ...can be either true or false.
- ...is never true.
-
Let $E \subseteq M$, and suppose $E$ is not closed.
Then $\overline{E}$ is not open.
- True.
- There is at least one example where this holds, and at least one where it fails.
- There are no examples where this is true.
-
Suppose $E \subseteq M$.
Then $E^\circ \subseteq \overline{E}$.
(I.e., the interior of $E$ is a (not necessarily proper) subset of the closure of $E$.)
- True.
- There is at least one example where this holds, and at least one where it fails.
- There are no examples where this is true.
-
Let $S = (-\infty, 0) \cup [1, 2) \cup \set{3 + \frac1n\mid n \in \N} \subset \R$.
Which of the following is not a limit point of $S$?
- $0$
- $1$
- $\frac32$
- $3+\frac1{10000}$