The VII AMMCS International Conference

Waterloo, Ontario, Canada | August 17-21, 2026

AMMCS 2026 Semi-Plenary Speaker

Large Coherent Structures in Wave Equations via Computer Assisted Proofs

Eduard-Wilhelm Kirr, University of Illinois at Urbana-Champaign

While coherent structures play an essential role in the analysis and applications of wave equations it has been impossible (until now) to find all the nonlinear ones. This talk will focus on the Nonlinear Schrodinger Equations where coherent structures have the form e iEtf(x) with real frequency E and the profile f in the H1 Sobolev space over Rn. We show that all coherent structures must organize themselves in smooth branches accumulating to E equal infinity. In this limit they split into peaks and an algebraic equilibrium equation between peak-potential and peak-peak interaction emerges. The equation determines the possible limit points of the coherent structures as the frequency E approaches infinity. For small number of peaks or for peaks in a collinear configuration the limiting points can be obtained by hand. However, for large number of non-collinear peaks we employ computer assisted proofs. Once the limit points are determined we adapt techniques from local bifurcation theory to show existence of actual branches of coherent states emerging from the limit points and trace them from high frequency into the range of medium and small frequency.
Eduard-Wilhem Kirr is currently an associate professor in the Mathematics Department at University of Illinois Urbana-Champaign. He obtained his Ph.D. in Mathematics from University of Michigan in 2002 under the direction of Michael I Weinstein and Anthony Bloch and was a Dickson Instructor at University of Chicago from 2002 to 2005 under the direction of Peter Constantin. During his graduate studies he was also a summer intern at Bell Laboratories. His main research interests focus on studying wave propagation and wave interaction using both theoretical methods and numerical simulations