Coarse Baum-Connes and coarse Novikov conjectures

Establish that for every metric space X with bounded geometry, the coarse assembly map μ: lim_{d→∞} K_*(P_d(X)) → K_*(C^*(X)) is an isomorphism; equivalently, show that the coarse Novikov conjecture holds by proving μ is injective.

Background

The paper recalls Roe algebras C*(X) and localization algebras, and defines the coarse assembly map μ: lim_{d→∞} K_(P_d(X)) → K_(C*(X)), where P_d(X) denotes the Rips complex of a bounded geometry metric space X. The coarse Baum-Connes conjecture predicts this assembly map is an isomorphism, while the coarse Novikov conjecture asks for injectivity only.

These conjectures connect large-scale geometry to operator K-theory and index theory. Throughout the paper, they serve as a benchmark and motivation for the relative versions formulated later, which use quotients of Roe algebras to detect refined obstructions to positive scalar curvature at infinity.

References

The coarse Baum-Connes conjecture (coarse Novikov conjecture, resp.) claims the assembly map \mu is an isomorphism (injection, resp.).

Relative higher index theory on quotients of Roe algebras and positive scalar curvature at infinity  (2509.23380 - Guo et al., 27 Sep 2025) in Section 2.1 (Roe algebras)