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Divergence-form operators with stationary random coefficients homogenize over large scales. We investigate the effect of certain perturbations of the medium on the homogenized coefficients. The perturbations considered are rare at the local level, but when ...
We consider a family of elliptic equations introduced in the context of traffic congestion. They have the form del . (del F(del u)) = f where F is a convex function which vanishes inside some convex set and is elliptic outside. Under some natural assumptio ...
We discuss three types of problems. The first one involves Jacobian equations and the two others involve Hessian equations. We proceed by fixed point, obtaining the results under a smallness assumption. ...
The quantum antiferromagnet Cu2Te2O5Br2 was investigated by NMR and nuclear quadrupole resonance (NQR). The Te-125 NMR investigation showed that there is a magnetic transition around 10.5 K at 9 T, in agreement with previous studies. From the divergence of ...
In this thesis, we study some linear and nonlinear problems involving differential forms. We begin by studying the problem of pullbacks which asks the following question: for two given differential forms, if one is the pullback of the other via a diffeomor ...
We apply the Ewald acceleration technique to the efficient evaluation of periodic Green's functions (GFs) for 3-D skewed lattices like those arising in electromagnetic/photonic band-gap (EBG/PBG) structures and metamaterials (MTMs). We develop the expressi ...
2007
Let f be an integrable function on RN, a a point in RN and B a complex number. If the mean value of f on the sphere of centre a and radius r tends to B when r tends to 0, we show that the Fourier integral at a of f is summable to B in Cesàro means of order ...
We consider a family of degenerate elliptic equations of the form div(del F(del u)) = f, where F is an element of C-1,C-1 is a convex function which is elliptic outside a ball. We prove an excess-decay estimate at points where del u is close to a nondegene ...
We present nonquadratic Hessian-based regularization methods that can be effectively used for image restoration problems in a variational framework. Motivated by the great success of the total-variation (TV) functional, we extend it to also include second- ...
We extend the mimetic finite difference (MFD) method to the numerical treatment of magnetostatic fields problems in mixed div-curl form for the divergence-free magnetic vector potential. To accomplish this task, we introduce three sets of degrees of freedo ...
