Path space (algebraic topology)
# Path space (algebraic topology)

In algebraic topology, a branch of mathematics, the path space $PX$ of a based space $(X,*)$ is the space that consists of all maps $f$ from the interval $I=[0,1]$ to X such that $f(0)=*$, called paths. In other words, it is the mapping space from $(I,0)$ to $(X,*)$.

The space $X^{I}$ of all maps from $I$ to X (free paths or just paths) is called the free path space of X. The path space $PX$ can then be viewed as the pullback of $X^{I}\to X,\,\chi \mapsto \chi (0)$ along $*\hookrightarrow X$.

The natural map $PX\to X,\,\chi \to \chi (1)$ is a fibration called the path space fibration.

