Displaying similar documents to “Boundary conditions for the Einstein-Christoffel formulation of Einstein's equations.”

Positive solutions with given slope of a nonlocal second order boundary value problem with sign changing nonlinearities

P. Ch. Tsamatos (2004)

Annales Polonici Mathematici

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We study a nonlocal boundary value problem for the equation x''(t) + f(t,x(t),x'(t)) = 0, t ∈ [0,1]. By applying fixed point theorems on appropriate cones, we prove that this boundary value problem admits positive solutions with slope in a given annulus. It is remarkable that we do not assume f≥0. Here the sign of the function f may change.

Well Posedness of Balance Laws with Non-Characteristic Boundary

Rinaldo M. Colombo, Massimiliano D. Rosini (2007)

Bollettino dell'Unione Matematica Italiana

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This note presents a well posedness result for the initial-boundary value problem consisting of a nonlinear system of hyperbolic balance laws with boundary, in the non-characteristic case.

Divergence boundary conditions for vector Helmholtz equations with divergence constraints

Urve Kangro, Roy Nicolaides (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

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The idea of replacing a divergence constraint by a divergence boundary condition is investigated. The connections between the formulations are considered in detail. It is shown that the most common methods of using divergence boundary conditions do not always work properly. Necessary and sufficient conditions for the equivalence of the formulations are given.