Functorial CW-approximation
arXiv:1508.01944
Abstract
The usual construction of a CW-approximation is functorial up to homotopy, but it is not functorial. In this note, we construct a functorial CW-approximation. Our construction takes inclusions of subspaces into inclusions of subcomplexes, and commutes with intersections of subspaces of a fixed space.
arXiv comment10 pages