Gałęski's local smooth rank-constrained approximation conjecture

About 8 years old · traced to

Let 1≤m<n1\leq m<n be integers and let Ω⊂Rn\Omega\subset\mathbb R^n be open. If f∈C1(Ω,Rn)f\in C^1(\Omega,\mathbb R^n) satisfies rank⁡Df≤m\operatorname{rank} Df\leq m everywhere in Ω\Omega, then for every point x∈Ωx\in\Omega there is a neighborhood Bn(x,ε)⊂Ω\mathbb B^n(x,\varepsilon)\subset\Omega and a sequence fi∈C∞(Bn(x,ε),Rn)f_i\in C^\infty(\mathbb B^n(x,\varepsilon),\mathbb R^n) such that rank⁡Dfi≤m\operatorname{rank} Df_i\leq m and fif_i converges to ff uniformly on Bn(x,ε)\mathbb B^n(x,\varepsilon).

Gałęski's local approximation conjecture. Every such mapping admits, around each point, a uniformly convergent smooth approximation sequence preserving the derivative-rank bound.

The paper states that this weaker local form is also false in general, with the main result providing counterexamples for certain ranges of nn and mm.

References

Primary source

Paweł Goldstein and Piotr Hajłasz, “C^1 mappings in R^5 with derivative of rank at most 3 cannot be uniformly approximated by C^2 mappings with derivative of rank at most 3”, arXiv:1804.08289 (2018).

Progress summary

Never refreshed

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

Solutions 0

No solutions have been posted yet.