In the study of stratified spaces it is useful to examine spaces of popaths (paths which travel from lower strata to higher strata) and holinks (those spaces of popaths which immediately leave a lower stratum for their final stratum destination). It is not immediately clear that for adjacent strata these two path spaces are homotopically equivalent, and even less clear that this equivalence can be constructed in a useful way (with a deformation of the space of popaths which fixes start and end points and where popaths instantly become members of the holink). The advantage of such an equivalence is that it allows a stratified space to be viewed categorically because popaths, unlike holink paths (which are easier to study), can be composed. This paper proves the aforementioned equivalence in the case of Quinn's homotopically stratified spaces [1].
Journal of Homotopy and Related Structures, Vol. 4(2009), No. 1, pp. 265-273