Regular directed path and Moore flow
Philippe Gaucher
TL;DR
This work develops canonical, tameness-aware realizations of precubical sets within a Moore-flow framework, defining tame regular realizations $|K|^t_{reg}$ and regular realizations $|K|_{reg}$ as multipointed $d$-spaces whose execution paths capture true concurrent behavior. It proves that the associated Moore-flow functor is weakly equivalent, up to the $h$-model structure, to a colimit-preserving replacement $[-]_{reg}$, with $[K]_{reg}$ being $m$-cofibrant and coinciding with ${oldsymbol M}^{oldsymbol G}(|K|^t_{reg})$ for spatial precubical sets. The paper builds a cube-chain–based realization, relates tameness to $L_1$-arc length, and shows that spaces of tame regular $d$-paths are homotopy equivalent to CW-complexes in a purely model-category framework. It further compares tame and regular realizations, establishing natural weak equivalences and highlighting when they align, thereby providing a robust, canonical, and cofibrant-friendly perspective on path spaces in concurrent computation models.
Abstract
Using the notion of tame regular $d$-path of the topological $n$-cube, we introduce the tame regular realization of a precubical set as a multipointed $d$-space. Its execution paths correspond to the nonconstant tame regular $d$-paths in the geometric realization of the precubical set. The associated Moore flow gives rise to a functor from precubical sets to Moore flows which is weakly equivalent in the h-model structure to a colimit-preserving functor. The two functors coincide when the precubical set is spatial, and in particular proper. As a consequence, it is given a model category interpretation of the known fact that the space of tame regular $d$-paths of a precubical set is homotopy equivalent to a CW-complex. We conclude by introducing the regular realization of a precubical set as a multipointed $d$-space and with some observations about the homotopical properties of tameness.
