A Note on Kohn’s and Christ’s Examples

  • Cesare Parenti
  • Alberto Parmeggiani
Part of the Trends in Mathematics book series (TM)


We give here a family of second order examples tailored to those by Kohn and by Christ, which are (C ) hypoelliptic and lose an arbitrarily large (fixed) number of derivatives.


Localize Operator Symplectic Manifold Complex Vector Hermite Operator Principal Symbol 
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Copyright information

© Birkhäuser Verlag Basel/Switzerland 2006

Authors and Affiliations

  • Cesare Parenti
    • 1
  • Alberto Parmeggiani
    • 2
  1. 1.Department of Computer ScienceUniversity of BolognaBolognaItaly
  2. 2.Department of MathematicsUniversity of BolognaBolognaItaly

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