We prove that the Cauchy problem for the dispersion generalized Benjamin-Ono equation ∂tu+ |∂x| ∂xu+ uux = 0, u(x, 0) = u0(x), is locally well-posed in the Sobolev spaces H for s > 1 − α if 0 ≤ α ≤ 1. The new ingredient is that we develop the methods of Ionescu, Kenig and Tataru [13] to approach the problem in a less perturbative way, in spite of the ill-posedness results of Molinet, Saut and T...

We study the local well-posedness of nonlinear Schrödinger equation associated to Grushin operator with random initial data. To best our knowledge, no result is known in Sobolev spaces Hk when k⩽32. In this article, we prove that there exists a large family data such that, respect suitable randomization Hk, k∈(1,32], almost-sure holds. The proof relies on bilinear and trilinear estimates.

We prove that the 1D Schrödinger equation with derivative in the nonlinear term is globally well-posed in H s , for s > 2/3 for small L 2 data. The result follows from an application of the " I-method ". This method allows to define a modification of the energy norm H 1 that is " almost conserved " and can be used to perform an iteration argument. We also remark that the same argument can be us...

It is shown that the Cauchy problem associated to the derivative nonlinear Schrödinger equation ∂tu − i∂ xu = λ∂x(|u| u) is locally well-posed for initial data u(0) ∈ H(T), if s ≥ 1 2 and λ is real. The proof is based on an adaption of the gauge transformation to periodic functions and sharp multi-linear estimates for the gauge equivalent equation in Fourier restriction norm spaces. By the use ...

Fourth-order Schrödinger equations have been introduced by Karpman and Shagalov to take into account the role of small fourth-order dispersion terms in the propagation of intense laser beams in a bulk medium with Kerr nonlinearity. In this paper we investigate the cubic defocusing fourth order Schrödinger equation i∂tu +∆ 2 u + |u|u = 0 in arbitrary space dimension R for arbitrary initial data....

We show under mild assumptions that a composition of internally well-posed, impedance passive (or conservative) boundary control systems through Kirchhoff type connections is also an internally well-posed, impedance passive (resp., conservative) boundary control system. The proof is based on results of [21]. We also present an example of such composition involving Webster’s equation on a Y-shap...

The focus of the present study is the BBM equation which models unidirectional propagation of small amplitude, long waves in dispersive media. This evolution equation has been used in both laboratory and field studies of water waves. The principal new result is an exact theory of convergence of the two-point boundary-value problem to the initial-value problem posed on an infinite stretch of the...