Riesz transforms and uniform rectifiability in higher codimensionOpen Problem
Motivation
Singular integral estimates can detect geometric regularity in a measure whose support has no given parametrization. The mission turns a uniform Riesz-transform bound into uniform pieces of Lipschitz images. The source manuscript presents the surrounding research claim.
Setting
Let μ be a regular measure in ℝᵈ, with d≥4 and 2≤n≤d−2. Ahlfors–David regularity means that μ(B(x,r)) is comparable to rⁿ on its support at admissible radii. Hard-truncated Riesz transforms use the kernel (x−y)/|x−y|^(n+1), excluding distances at most ε.
Formalization target
With fixed dimension and bounds C_AD,C_R, prove that there exist θ>0 and M≥0 such that every eligible μ satisfies
for some M-Lipschitz map g from the open n-dimensional radius-r ball, at every support point and admissible radius.
The selected formal target is OAI.RieszRectifiability.quantitative_higher_codimension_riesz_rectifiability.
Significance and status
The constants θ and M are uniform across the entire class of measures with the prescribed analytic bounds. This is the exact quantitative ball-image conclusion. The published target is currently Open; the manuscript's argument and a checked Lean proof are separate deliverables.
Difficulty
Individual rectifiable pieces with constants depending on μ do not yield this quantifier order. The Riesz bound ranges over every positive hard truncation and every scalar L² input.
Formalization scope
Ambient space is EuclideanSpace ℝ (Fin d). Radii are positive and bounded by the extended support diameter. The hypothesis uses μ.Regular, nonnegative Riesz constants, MemLp and eLpNorm; the conclusion uses the actual measure of the intersection with a Lipschitz image. No endpoint codimensions are included.
Selected references
- OpenAI, Riesz transforms and uniform rectifiability in higher codimension, preprint, 2026. Pinned manuscript.
- OpenAI, accompanying formal statements, commit
adc7f1241b42. Goal source.