Definition:Path Component

From ProofWiki
Jump to navigation Jump to search

Definition

Let $T$ be a topological space.


Equivalence Class

Let $\sim$ be the equivalence relation on $T$ defined as:

$x \sim y \iff x$ and $y$ are path-connected.

The equivalence classes of $\sim$ are called the path components of $T$.

If $x \in T$, then the path component of $T$ containing $x$ (that is, the set of points $y \in T$ with $x \sim y$) can be denoted by $\map {\operatorname{PC}_x} T$.


Union of Path-Connected Sets

The path component of $T$ containing $x$ is defined as:

$\ds \map {\operatorname{PC}_x} T = \bigcup \leftset {A \subseteq S: x \in A \land A}$ is path-connected $\rightset {}$


Maximal Path-Connected Set

The path component of $T$ containing $x$ is defined as:

the maximal path-connected set of $T$ that contains $x$.


Also see