Cauchy problem for effectively hyperbolic operators with triple characteristics of variable multiplicity
Langue
en
Article de revue
Ce document a été publié dans
Journal of Hyperbolic Differential Equations. 2015-09, vol. 12, n° 3, p. 535-579.
World Scientific Publishing
Résumé en anglais
We study a class of third order hyperbolic operators $P$ in $G = \{(t, x):0 \leq t \leq T, x \in U \Subset \R^{n}\}$ with triple characteristics at $\rho = (0, x_0, \xi), \xi \in \R^n \setminus \{0\}$. We consider the case ...Lire la suite >
We study a class of third order hyperbolic operators $P$ in $G = \{(t, x):0 \leq t \leq T, x \in U \Subset \R^{n}\}$ with triple characteristics at $\rho = (0, x_0, \xi), \xi \in \R^n \setminus \{0\}$. We consider the case when the fundamental matrix of the principal symbol of $P$ at $\rho$ has a couple of non-vanishing real eigenvalues. Such operators are called {\it effectively hyperbolic}. V. Ivrii introduced the conjecture that every effectively hyperbolic operator is {\it strongly hyperbolic}, that is the Cauchy problem for $P + Q$ is locally well posed for any lower order terms $Q$. This conjecture has been solved for operators having at most double characteristics and for operators with triple characteristics in the case when the principal symbol admits a factorization. A strongly hyperbolic operator in $G$ could have triple characteristics in $G$ only for $t = 0$ or for $t = T$. We prove that the operators in our class are strongly hyperbolic if $T$ is small enough. Our proof is based on energy estimates with a loss of regularity.< Réduire
Mots clés en anglais
Cauchy Problem
Effectively Hyperbolic Operators
Triple Characteristics
Energy estimates
Project ANR
Opérateurs non-autoadjoints, analyse semiclassique et problèmes d'évolution - ANR-11-BS01-0019
Origine
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