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arXiv · 2603.01939

Dispersive estimates for a system of tensorial quasilinear wave equations satisfying the weak-null condition

Sari Ghanem
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Abstract

We establish both global existence and decay properties for solutions with small data for a general class of coupled system of tensorial quasilinear hyperbolic wave equations in three space dimensions, that covers the dynamical Einstein equations coupled to a class of non-linear matter sources that do not satisfy the null condition of Christodoulou and Klainerman, and have new different non-linearities than the one treated by Lindblad-Rodnianski, for which their celebrated seminal $L^\infty$-estimate does not work, to the best of our knowledge. Global existence of solutions for a general class of quasilinear wave equations satisfying the weak-null condition, with small initial data, is largely an open problem at present. There is no known theory to prove decay for the class of non-linear hyperbolic partial differential equations that we treat in this paper. We establish a technique based on novel decoupling of the higher order energy estimates, at the level of the $L^2$-norm of the Lie derivatives of the tangential components, without involving all the other components, up to some good factor. This generalizes our previous results to include new non-linearities that are not present in the Einstein-Yang-Mills system in the Lorenz gauge.

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Sari Ghanem. 2026-03-02. Dispersive estimates for a system of tensorial quasilinear wave equations satisfying the weak-null condition. https://arxiv.org/abs/2603.01939

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