Aktuelles

Mittwoch, 19.11.2025: Quadratically enriched plane curve counting via tropical geometry

Felix Röhrle (Tübingen)

Consider the classical problem in enumerative geometry of counting rational plane curves through a fixed configuration of points. The problem may be considered over any base field and the point conditions might be scheme theoretic points. Recently, Kass--Levine--Solomon--Wickelgren have used techniques from $\mathbb{A}1^^1^$-homotopy theory to define an enumerative invariant for this problem which is defined over a large class of possible base fields. This new theory generalizes Gromov-Witten invariants (base field = complex numbers) and Welschinger invariants (base field = real numbers) simultaneously. In this talk I will present a tropical correspondence theorem, which allows to effectively compute these new invariants. This is joint work with Andrès Jaramillo-Puentes, Hannah Markwig, and Sabrina Pauli.

Uhrzeit:	10:15 - 11:15
Ort:	S10
Gruppe:	Oberseminar kombinatorische algebraische Geometrie
Einladender:	Daniele Agostini, Hannah Markwig

Donnerstag, 20.11.2025: Boosts of the STCMC Center of Mass

Saradha Senthil-Velu (Universität Tübingen)

In this talk, we will briefly review definitions of center of mass and angular momentum for asymptotically Euclidean initial data sets. The focus is the behavior of the spacetime constant–mean–curvature (STCMC) center under boosts. After clarifying boost notions and motivating the physically correct one for charge evolution, we will see that in model graphical cases in Schwarzschild the STCMC center transforms exactly as expected, in contrast to the constant–mean–curvature (CMC) center. Beyond this model class, we establish the linearized boost law for infinitesimal boosts of the STCMC center. Altogether, the STCMC center fits naturally into the asymptotic Poincaré structure of the ambient spacetime: it transforms correctly under boosts without imposing strong Regge–Teitelboim parity conditions, only weaker decay/parity hypotheses.

Uhrzeit:	14:00
Ort:	Seminarraum C4H33 and virtual via zoom, for zoom link please contact Martina Neu
Gruppe:	Oberseminar Geometrische Analysis, Differentialgeometrie und Relativitätstheorie
Einladender:	Carla Cederbaum, Gerhard Huisken, zusammen mit Jan Metzger (Potsdam)

Donnerstag, 20.11.2025: Mean curvature flow analogues in Cauchy-Riemann (CR) Geometry

Marcus Flook (ANU)

In this talk, I will introduce and motivate Cauchy-Riemann (CR) geometry by considering real hypersurfaces embedded in complex Euclidean space. Firstly, I will discuss progress on both Darboux- and Alexandrov-type theorems in this setting. Secondly, I will introduce flows of CR hypersurfaces that are analogous to the mean curvature flow. Alongside the standard degeneracy due to tangential diffeomorphisms, such flows have an additional degeneracy due to the CR structure which will be discussed. Finally, I will discuss joint research with Ben Andrews on new flows which preserve key components of the CR structure.

Uhrzeit:	15:00
Ort:	Seminarraum C4H33 and virtual via zoom, for zoom link please contact Martina Neu
Gruppe:	Oberseminar Geometrische Analysis, Differentialgeometrie und Relativitätstheorie
Einladender:	Carla Cederbaum, Gerhard Huisken, zusammen mit Jan Metzger (Potsdam)