### Info

This seminar features recent results at the intersection of high-energy physics, string theory, and geometry and topology.

** Prerequisites:** None. Everyone is welcome. To receive announcements for
this seminar, and for the advertisement of other talks at the intersection of physics and
geometry in Heidelberg,
you may subscribe to the
Mailing List.

** Time and Place:** Regularly: Monday, 2 p.m.s.t., MATHEMATIKON
SR 3

Alternatively: Tuesday or Thursday, 2 p.m.s.t., various locations (or as noted below).

** Online seminar:** Due to the coronavirus crisis the seminar is held online in cooperation with LMU Munich and University of Vienna. Please contact the organizers per e-mail to receive the link to the online seminar.

Current time is Monday, 4 p.m.c.t..

### Online Vorträge

Date | Speaker | Title, Abstract |
---|---|---|

February 17 | Navid Nabijou (Glasgow) | Tangent curves, degenerations, and blowups |

It is well-known that every smooth plane cubic E supports precisely 9 flex lines. By analogy, we may ask: "How many degree d curves intersect E in a single point?" The problem of calculating such numbers of tangent curves has fascinated enumerative geometers for decades. Despite being an extremely classical and concrete problem, it was not until the advent of Gromov-Witten invariants in the 1990s that a general method was discovered. The resulting theory is incredibly rich, and the curve counts satisfy a suite of remarkable properties, some proven and some still conjectural.
In this talk, I will discuss two distinct projects which take inspiration from this geometry. In the first, joint with Lawrence Barrott, we study the behaviour of tangent curves as the cubic E degenerates to a cycle of lines. Using the machinery of logarithmic Gromov-Witten theory, we obtain detailed information concerning how the tangent curves degenerate along with E. The resulting theorems are purely classical, with no reference to Gromov-Witten theory, but they do not appear to admit a classical proof. In a separate project, joint with Dhruv Ranganathan, we perform iterated blowups of moduli spaces to prove the so-called local-logarithmic conjecture for hyperplane sections; this gives access to a large number of previously unknown enumerative theories. No prior knowledge of Gromov-Witten theory will be assumed. |
||

Mai 5 | Ivo Sachs (Munich) | From BV to string theory and back |

Mai 18 | Nils Carqueville (Vienna) | An introduction to functorial TQFT with defects |

Mai 25 | Christoph Chiaffrino (Munich) | Planar Quantum A-Infinity Algebras |

June 8 | Ingmar Saberi (Heidelberg) | TBA |

June 15 | N.N. | TBA |

June 22 | N.N. | TBA |

June 29 | N.N. | TBA |

July 6 | N.N. | TBA |

### Veranstalter

Prof. J. Walcher, walcher@uni-heidelberg.de

Dr. Ingmar Saberi,
saberi@mathi.uni-heidelberg.de