Milman's contracting transport conjecture for positively Ricci-curved spheres

From papers

Let dd be a positive integer, let (Sd,g)(\mathbb{S}^d,g) be a Riemannian sphere with volume measure volg\operatorname{vol}_g, and suppose that

Ricgρg\operatorname{Ric}_g\geq \rho g

for some ρ>0\rho>0. Let gcanρg^\rho_{\mathrm{can}} be the canonical metric on Sd\mathbb{S}^d rescaled so that

Ricgcanρ=ρgcanρ.\operatorname{Ric}_{g^\rho_{\mathrm{can}}}=\rho g^\rho_{\mathrm{can}}.

Milman's contracting transport conjecture. There exists a map

T:(Sd,gcanρ,volgcanρ)(Sd,g,volg)T:(\mathbb{S}^d,g^\rho_{\mathrm{can}},\operatorname{vol}_{g^\rho_{\mathrm{can}}})\to(\mathbb{S}^d,g,\operatorname{vol}_g)

that pushes forward volgcanρ\operatorname{vol}_{g^\rho_{\mathrm{can}}} onto volg\operatorname{vol}_g up to a finite constant and contracts the corresponding metrics. This is a finite-dimensional analogue of the Gaussian contraction theorem, but the supplied text gives no resolution status for it.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

Shrey Aryan, “Spectral Obstructions to Contracting Transport Maps on Curved Spaces”, arXiv:2605.24705 (2026).

Solutions 0

No solutions have been posted yet.