We construct examples of nondegenerate CR manifolds with Levi form of signature , , which are compact, not locally CR flat, and admit essential CR vector fields. We also construct an example of a noncompact nondegenerate CR manifold with signature that is not locally CR flat and admits an essential CR vector field. These provide counterexamples to the analogue of the Lichnerowicz conjecture for CR manifolds with mixed signature.
Nous construisons des exemples de variétés CR non dégénérées avec une forme de Levi de signature , , qui sont compactes, non localement CR plates et admettent des champs de vecteurs CR essentiels. Nous construisons également un exemple d'une variété CR non dégénérée et non compacte, de signature , qui n'est pas localement CR plate et admet un champ de vecteurs CR essentiel. Ceci fournit des contre-exemples aux analogues de la conjecture de Lichnerowicz pour les variétés CR de signature mixte.
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Jeffrey S. Case 1; Sean N. Curry 2; Vladimir S. Matveev 3
@article{CRMATH_2018__356_5_532_0, author = {Jeffrey S. Case and Sean N. Curry and Vladimir S. Matveev}, title = {On the {Lichnerowicz} conjecture for {CR} manifolds with mixed signature}, journal = {Comptes Rendus. Math\'ematique}, pages = {532--537}, publisher = {Elsevier}, volume = {356}, number = {5}, year = {2018}, doi = {10.1016/j.crma.2018.03.012}, language = {en}, }
TY - JOUR AU - Jeffrey S. Case AU - Sean N. Curry AU - Vladimir S. Matveev TI - On the Lichnerowicz conjecture for CR manifolds with mixed signature JO - Comptes Rendus. Mathématique PY - 2018 SP - 532 EP - 537 VL - 356 IS - 5 PB - Elsevier DO - 10.1016/j.crma.2018.03.012 LA - en ID - CRMATH_2018__356_5_532_0 ER -
Jeffrey S. Case; Sean N. Curry; Vladimir S. Matveev. On the Lichnerowicz conjecture for CR manifolds with mixed signature. Comptes Rendus. Mathématique, Volume 356 (2018) no. 5, pp. 532-537. doi : 10.1016/j.crma.2018.03.012. https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.1016/j.crma.2018.03.012/
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