The weak-integrability conjectures for Alexandrov submetries

From papers

Let f:XYf:X\to Y be a submetry with XAlexn(κ)X\in \operatorname{Alex}^n(\kappa) and YAlexm(κ)Y\in \operatorname{Alex}^m(\kappa). A submetry is weakly integrable when the local isometric pieces in the source's definition exist, and integrable when in addition their spaces of directions equal the horizontal spaces.

Weak-integrability conjectures. (1) If Y=\partial Y=\emptyset and ff is weakly integrable, then ff is integrable. (2) If ΣAlexn(1)\Sigma\in \operatorname{Alex}^n(1), Σ0Alexm(1)\Sigma_0\in \operatorname{Alex}^m(1), Σ0=\partial\Sigma_0=\emptyset, and h:ΣΣ0h:\Sigma\to\Sigma_0 is weakly integrable, then n=mn=m.

The source states that these two assertions are equivalent and that they fail when the boundary restrictions are removed. It also notes that the first is immediate for Riemannian manifolds, while the second remains nontrivial there.

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Sources & referencesView supporting material

Primary source

Xueping Li and Xiaochun Rong, “Open Alexandrov spaces of nonnegative curvature”, arXiv:2311.15174 (2025).

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