The sub-Riemannian Sard conjecture asserts that, for every smooth bracket-generating distribution on a manifold and every initial point
,
the endpoints of abnormal curves starting at 
have measure zero (Wang and Zelenko 2026).
Wang and Zelenko (2026) constructed an equiregular distribution of rank two on a manifold 
diffeomorphic to 
, with growth vector 
, for which every point of 
is the endpoint of an abnormal
curve starting at the origin. The result does not
contradict Sard's theorem for maps between finite-dimensional
manifolds. It also does not settle the different question
restricted to length-minimizing curves.
Wang and Zelenko (2026) report that the lifting strategy was proposed by Zelenko, while Claude generated the explicit construction and initial proofs. The authors checked and revised the argument, particularly its analytic part. They also report a Codex-assisted Lean formalization of the main theorems.
