# Path space

The space $E$ of the fibre space $(E,p,X)$, which is called the path fibre space. Here $X$ is a path-connected space with a distinguished point $*$, $E$ is the set of paths in $X$ starting from $*$ and $p$ is the mapping associating to each path its end-point. Moreover, $E$ is considered to have the compact-open topology. The fibre of this fibre space (which is a Serre fibration) is the loop space $\Omega X$ — the set of all loops (cf. Loop (in topology)) in $X$ at $*$. A path space can be contracted within itself to a point, so the homotopy groups $\pi_n(E)=0$, and the homotopy sequence of the path fibre space degenerates into the so-called Hurewicz isomorphisms:

$$\pi_n(\Omega X)\approx\pi_{n+1}(X).$$

#### Comments

#### References

[a1] | E.H. Spanier, "Algebraic topology" , McGraw-Hill (1966) pp. 75ff, 99ff |

**How to Cite This Entry:**

Path space.

*Encyclopedia of Mathematics.*URL: http://www.encyclopediaofmath.org/index.php?title=Path_space&oldid=39527