A counterexample to 𝐶^{𝑘}-regularity for the Newlander-Nirenberg theorem

Yao, Liding

doi:10.1090/proc/15270

A counterexample to $C^k$-regularity for the Newlander-Nirenberg theorem
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Proc. Amer. Math. Soc. 149 (2021), 1111-1115

Abstract:

We give an example of a $C^k$-integrable almost complex structure that does not admit a corresponding $C^{k+1}$-complex coordinate system.

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