\( \newcommand{\matr}[1] {\mathbf{#1}} \newcommand{\vertbar} {\rule[-1ex]{0.5pt}{2.5ex}} \newcommand{\horzbar} {\rule[.5ex]{2.5ex}{0.5pt}} \)
header
Show Answer
\( \newcommand{\cat}[1] {\mathrm{#1}} \newcommand{\catobj}[1] {\operatorname{Obj}(\mathrm{#1})} \newcommand{\cathom}[1] {\operatorname{Hom}_{\cat{#1}}} \)
Math and science::Analysis::Tao::09. Continuous functions on R

Limit points and isolated points (of sets of reals), definition

Limit points

Let \( X \) be a subset of the real line. We say that \( x \) is a limit point (or cluster point) of \( X \) if [...].

Not to be confused with limit points of sequences.

Isolated points

Let \( X \) be a subset of the real line. We say that \( x \) is an isolated point of \( X \) if \( x \in X \) and [...].