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Inhaltsverzeichnis - Mathematisches Institut der Universität zu Köln

Inhaltsverzeichnis - Mathematisches Institut der Universität zu Köln

Inhaltsverzeichnis - Mathematisches Institut der Universität zu Köln

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Juliette Hell<br />

Freie <strong>Universität</strong> Berlin<br />

Dynamics at Infinity<br />

DMV Tagung 2011 - <strong>Köln</strong>, 19. - 22. September<br />

We interpret blow-up phenomena as heteroclinic orbits connecting a bounded invariant set to infinity. The<br />

question addressed is: Which parts of the bounded dynamics give birth to exploding trajectories? Via<br />

Poincaré compactification, infinity is made accessible to topological methods of detection of heteroclinics,<br />

such as Conley index theory. Furthermore the artificial dynamics in the sphere at infinity provides information<br />

on the shape of the blow-up. This talk emphasizes applications of compactification methods to partial<br />

differential equations whose leading or<strong>der</strong> is a homogenous polynomial of degree d. In particular we will<br />

focus on slowly non-dissipative reaction-diffusion equations (joined work with Nitsan Ben-Gal).<br />

Literatur<br />

Nitsan Ben-Gal. Grow-Up Solutions and Heteroclinics to Infinity for Scalar Parabolic PDEs Ph.D. Thesis,<br />

Brown University, 2010,<br />

Juliette Hell. Conley Index at Infinity Doktorarbeit, Freie <strong>Universität</strong> Berlin, 2010<br />

Juliette Hell. Conley Index at Infinity. Preprint, arXiv:1103.5335v1<br />

Sebastian Herr<br />

<strong>Universität</strong> Bonn<br />

Nonlinear dispersive equations in critical spaces<br />

I will review harmonic analysis methods for solving the initial value problem associated to nonlinear<br />

dispersive evolution equations. For certain nonlinear Schrödinger equations and other interesting models<br />

such as the KP-II equation, the Zakharov system or pseudo-relativistic Hartree equations I am going<br />

to report on recent progress concerning the well-posedness problem in (approximately) scale-invariant<br />

Sobolev spaces.<br />

Vu Hoang<br />

GRK 1294/<strong>Institut</strong> für Analysis, Karlsruher <strong>Institut</strong> für Technologie (KIT)<br />

Analysis of semi-infinite periodic structures<br />

Traditionally, the Floquet transform is used to analyze periodic structures which are infinitely extended<br />

in all space directions. Since there is the possibility of building optical devices from photonic crystal<br />

materials, the mathematical un<strong>der</strong>standing of structures arising from the truncation of an infinite crystal<br />

is also of great importance. A typical model situation is a half-space of photonic crystal or a semi-infinite<br />

periodic waveguide; here, the un<strong>der</strong>lying domain is not invariant with respect to integer translations, so it<br />

is not clear how to apply Floquet-Bloch theory. In this talk, we give an overview of recent work leading<br />

to a new radiation condition for semi-infinite periodic structures and also to representation theorems for<br />

solutions of periodic problems in half-spaces.<br />

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