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Weakly regular T 2 -symmetric spacetimes. The global geometry of future Cauchy developments

Philippe LeFloch, Jacques Smulevici (2015)

Journal of the European Mathematical Society

We provide a geometric well-posedness theory for the Einstein equations within the class of weakly regular vacuum spacetimes with T 2 -symmetry, as defined in the present paper, and we investigate their global causal structure. Our assumptions allow us to give a meaning to the Einstein equations under weak regularity as well as to solve the initial value problem under the assumed symmetry. First, introducing a frame adapted to the symmetry and identifying certain cancellation properties taking place...

Weakly semibounded boundary problems and sesquilinear forms

Gerd Grubb (1973)

Annales de l'institut Fourier

Let A be a 2 m order differential operator in a hermitian vector bundle E over a compact riemannian manifold Ω ‾ with boundary Γ  ; and denote by A B the realization defined by a normal differential boundary condition B ρ u = 0 ( u ∈ H 2 m ( E ) , ρ u = Cauchy data). We characterize, by an explicit condition on A and B near Γ , the realizations A B for which there exists an integro-differential sesquilinear form a B ( u , ν ) on H m ( E ) such that ( A u , ν ) = a B ( u , ν ) on D ( A B ) ; moreover we show that these are exactly the realizations satisfying a weak semiboundedness estimate:...

Weak-strong uniqueness for a class of degenerate parabolic cross-diffusion systems

Philippe Laurençot, Bogdan-Vasile Matioc (2023)

Archivum Mathematicum

Bounded weak solutions to a particular class of degenerate parabolic cross-diffusion systems are shown to coincide with the unique strong solution determined by the same initial condition on the maximal existence interval of the latter. The proof relies on an estimate established for a relative entropy associated to the system.

Weak-strong uniqueness for Navier-Stokes/Allen-Cahn system

Radim Hošek, Václav Mácha (2019)

Czechoslovak Mathematical Journal

The coupled Navier-Stokes/Allen-Cahn system is a simple model to describe phase separation in two-component systems interacting with an incompressible fluid flow. We demonstrate the weak-strong uniqueness result for this system in a bounded domain in three spatial dimensions which implies that when a strong solution exists, then a weak solution emanating from the same data coincides with the strong solution on its whole life span. The proof of given assertion relies on a form of a relative entropy...

Weighted Dispersive Estimates for Solutions of the Schrödinger Equation

Cardoso, Fernando, Cuevas, Claudio, Vodev, Georgi (2008)

Serdica Mathematical Journal

2000 Mathematics Subject Classification: 35L15, 35B40, 47F05.Introduction and statement of results. In the present paper we will be interested in studying the decay properties of the Schrödinger group.The authors have been supported by the agreement Brazil-France in Mathematics – Proc. 69.0014/01-5. The first two authors have also been partially supported by the CNPq-Brazil.

Weighted energy-dissipation functionals for gradient flows

Alexander Mielke, Ulisse Stefanelli (2011)

ESAIM: Control, Optimisation and Calculus of Variations

We investigate a global-in-time variational approach to abstract evolution by means of the weighted energy-dissipation functionals proposed by Mielke and Ortiz [ESAIM: COCV14 (2008) 494–516]. In particular, we focus on gradient flows in Hilbert spaces. The main result is the convergence of minimizers and approximate minimizers of these functionals to the unique solution of the gradient flow. Sharp convergence rates are provided and the convergence analysis is combined with time-discretization....

Weighted energy-dissipation functionals for gradient flows

Alexander Mielke, Ulisse Stefanelli (2011)

ESAIM: Control, Optimisation and Calculus of Variations

We investigate a global-in-time variational approach to abstract evolution by means of the weighted energy-dissipation functionals proposed by Mielke and Ortiz [ESAIM: COCV14 (2008) 494–516]. In particular, we focus on gradient flows in Hilbert spaces. The main result is the convergence of minimizers and approximate minimizers of these functionals to the unique solution of the gradient flow. Sharp convergence rates are provided and the convergence analysis is combined with time-discretization....

Weighted estimates for commutators of linear operators

Josefina Alvarez, Richard Bagby, Douglas Kurtz, Carlos Pérez (1993)

Studia Mathematica

We study boundedness properties of commutators of general linear operators with real-valued BMO functions on weighted L p spaces. We then derive applications to particular important operators, such as Calderón-Zygmund type operators, pseudo-differential operators, multipliers, rough singular integrals and maximal type operators.

Weighted L² and L q approaches to fluid flow past a rotating body

R. Farwig, S. Kračmar, M. Krbec, Š. Nečasová, P. Penel (2009)

Banach Center Publications

Consider the flow of a viscous, incompressible fluid past a rotating obstacle with velocity at infinity parallel to the axis of rotation. After a coordinate transform in order to reduce the problem to a Navier-Stokes system on a fixed exterior domain and a subsequent linearization we are led to a modified Oseen system with two additional terms one of which is not subordinate to the Laplacean. In this paper we describe two different approaches to this problem in the whole space case. One of them...

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