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

The space ${\displaystyle X^{I}}$ of all maps from ${\displaystyle I}$ to X ( free paths or just paths) is called the free path space of X. [2] The path space ${\displaystyle PX}$ can then be viewed as the pullback of ${\displaystyle X^{I}\to X,\,\chi \mapsto \chi (0)}$ along ${\displaystyle *\hookrightarrow X}$. [1]

The natural map ${\displaystyle PX\to X,\,\chi \to \chi (1)}$ is a fibration called the path space fibration. [3]

## References

1. ^ a b Martin Frankland, Math 527 - Homotopy Theory - Fiber sequences
2. ^ Davis & Kirk 2001, Definition 6.14.
3. ^ Davis & Kirk 2001, Theorem 6.15. 2.
• Davis, James F.; Kirk, Paul (2001). Lecture Notes in Algebraic Topology (PDF). Graduate Studies in Mathematics. Vol. 35. Providence, RI: American Mathematical Society. pp. xvi+367. doi: 10.1090/gsm/035. ISBN  0-8218-2160-1. MR  1841974.