Displaying similar documents to “Superfixed positions in the geometry of Goursat flags.”

The proof of the Nirenberg-Treves conjecture

Nils Dencker (2003)

Journées équations aux dérivées partielles

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We prove the Nirenberg-Treves conjecture : that for principal type pseudo-differential operators local solvability is equivalent to condition ( Ψ ). This condition rules out certain sign changes of the imaginary part of the principal symbol along the bicharacteristics of the real part. We obtain local solvability by proving a localizable estimate for the adjoint operator with a loss of two derivatives (compared with the elliptic case). The proof involves a new metric in the Weyl (or Beals-Fefferman)...

An intrinsic definition of the Colombeau generalized functions

Jiří Jelínek (1999)

Commentationes Mathematicae Universitatis Carolinae

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A slight modification of the definition of the Colombeau generalized functions allows to have a canonical embedding of the space of the distributions into the space of the generalized functions on a 𝒞 manifold. The previous attempt in [5] is corrected, several equivalent definitions are presented.