Dice Question Streamline Icon: https://streamlinehq.com

Contravariant functoriality of E^∞ for open inclusions

Ascertain whether the local homology theory E^∞: UBC → 𝔻 has contravariant functoriality with respect to inclusions of open subsets, analogous to the contravariant functoriality known for the locally finite theory ΣE(*)^{lf}(-).

Information Square Streamline Icon: https://streamlinehq.com

Background

Within the framework of coarse and local homology theories, the authors construct two related functors: the locally finite homology theory ΣE(*){lf}(-), which possesses additional contravariant functoriality for inclusions of open subsets, and the local homology theory E derived from a strong coarse homology theory via the cone construction.

They highlight uncertainty about whether E enjoys the same contravariant functoriality as ΣE(*){lf}(-). Resolving this would clarify the naturality properties of E and potentially broaden its applicability in Mayer–Vietoris and excision contexts.

References

We do not know whether $E{\infty} (-)$ has such a contravariant functoriality.

Coronas and Callias type operators in coarse geometry (2411.01646 - Bunke et al., 3 Nov 2024) in Remark after Example kofpwerfeggrwrg, Subsection 'Local and locally finite homology theories'