Past Inverse problems talks

Time & Location: Tuesday, 11 November at 15:00, room MaD245

Speaker: Eetu Satukangas

Title: Tomography of 1-forms in gas giant geometry

Abstract: Gas giant geometry is a special type of Riemannian manifold with boundary that describes acoustic wave propagation in gas giant planets. In this presentation I will discuss some properties of the geometry and present a new result for the (solenoidal) injectivity of the geodesic ray transform of 1-forms in gas giant geometry. 

Time & Location: Tuesday, 4 November at 14:45, room MaD245

Speaker: Ashwin Tarikere Ashok Kumar Nag

Title: Propagation of polarization sets 

Abstract: We will study the concept of polarization sets for vector valued distributions, which is a refinement of wavefront sets introduced by Dencker in 1981. We will also look at how polarization sets propagate for solutions of systems of real principal type.

Time & Location: Tuesday, 28 October at 15:00, room MaD245

Speaker: Antonio Pop-Gorea

Title: Characterization of elastic reducibility in 2D 

Abstract: It has been shown in dimension two that slowness polynomials are generically irreducible. We give a characterization in dimension two that a stiffness tensor has to satisfy so that its induced slowness polynomial is stably solvable. We thus define the notion of a rectangular stiffness tensor and show that irreducibility of a slowness surface breaks down within this condition. Furthermore, we also show that uniqueness is no longer guaranteed and hence injectivity fails for rectangular stiffness tensors. In fact non-uniqueness is equivalent to rectangularity of a stiffness tensor. We also show that avoiding the rectangular stiffness tensors will lead to stability. All of these results then imply stable solvability for non-rectangular stiffness tensors. 

Time & Location: Tuesday, 21 October at 15:00, room MaD245

Speaker: Joonas Ilmavirta

Slides:📄

Title: Spectral perturbation theory

Time & Location: Tuesday, 14 October at 15:00, room MaD245

Speaker: Inverse problems research group

Title: Meet the Inverse problems research group

Abstract: All the speakers of the seminar series shortly introduce themselves and their research.