Methods and Applications of Analysis
Volume 9 (2002)
A convex Darboux Theorem
Pages: 329 – 344
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.