A two-step ideal sub-Riemannian structure with no measure contraction properties
Abstract
We construct a compact, equiregular, ideal sub-Riemannian manifold of step 2 such that, for every smooth positive measure, the MCP(K, N) fails for all K ∈ R and N ∈ (1, ∞). This shows that the real-analyticity assumption in the measure contraction theorem of Badreddine and Rifford in [Ann. Inst. Fourier, 2020] cannot be replaced by smoothness. Moreover, our structure is ideal, i.e. it admits no non-trivial abnormal minimizing geodesics. Although failures of the measure contraction property for ideal structures were recently obtained in the higher-step setting, our construction shows that the phenomenon can already occur on compact, equiregular, ideal structures of step 2. The proof exploits a differential consequence of the measure contraction property, namely a uniform upper bound for the sub-Laplacian of the squared distance near its base point, and constructs a structure for which this quantity is unbounded.
Related
- Biharmonic Wintgen ideal submanifolds in Riemannian manifolds of constant sectional curvature
- The measure contraction property and rectifiability
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- The measure contraction property on Grushin spaces
- Lp-Liouville properties and realizations of Schrödinger operators on incomplete Riemannian manifolds
BibTeX
@misc{rizzi2026twostep,
title = {{A two-step ideal sub-Riemannian structure with no measure contraction properties}},
author = {Luca Rizzi and Ye Zhang},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29698},
eprint = {2609.29698},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05753931v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - A two-step ideal sub-Riemannian structure with no measure contraction properties
AU - Luca Rizzi
AU - Ye Zhang
PY - 2026
DA - 2026/09/01
PB - HAL
DO - 10.48550/arxiv.2609.29698
UR - https://hal.science/hal-05753931v1
AB - We construct a compact, equiregular, ideal sub-Riemannian manifold of step 2 such that, for every smooth positive measure, the MCP(K, N) fails for all K ∈ R and N ∈ (1, ∞). This shows that the real-analyticity assumption in the measure contraction theorem of Badreddine and Rifford in [Ann. Inst. Fourier, 2020] cannot be replaced by smoothness. Moreover, our structure is ideal, i.e. it admits no non-trivial abnormal minimizing geodesics. Although failures of the measure contraction property for ideal structures were recently obtained in the higher-step setting, our construction shows that the phenomenon can already occur on compact, equiregular, ideal structures of step 2. The proof exploits a differential consequence of the measure contraction property, namely a uniform upper bound for the sub-Laplacian of the squared distance near its base point, and constructs a structure for which this quantity is unbounded.
ER -