Lángi Zsolt: Monotonicity of the isoperimetric ratio in the Eikonal model In the past decades, finding monotone quantities under various geometric PDEs has been in the focus of research. In this talk we investigate such a problem, and show that under the Eikonal abrasion model, which prescribes uniform normal speed in the direction of the inward surface normal, the isoperimetric quotient of a convex body is decreasing monotonically. The proof os based on tools from Brunn-Minkowski theory. The result may provide a possible explanation for the elongated shape of the extrasolar asteroid 'Oumuamua. Joint work with Gábor Domokos.