Methods and Applications of Analysis

Volume 9 (2002)

Number 3

A convex Darboux Theorem

Pages: 329 – 344



Ivar Ekeland

Louis Nirenberg


We give necessary and sufficent conditions for a smooth, generic, differential one-form w on Rn to decompose into a sum w = a1du1 +... +akduk, where the function a l are positive and the ul convex (or quasi-convex) near the origin.

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