| Sunday 1 June 2025 | |
| Events for day: Wednesday 19 February 2025 |
| 14:00 - 15:00 Combinatorics and Computing Weekly Seminar Approximating Prize-collecting Variants of the Traveling Salesman Problem School MATHEMATICS Many combinatorial optimization problems have been studied in the prize collecting setting, where the coverage requirement for an entity can be relaxed by paying a predefined penalty. This resembles the classical Lagrangian relaxation, and is natural in many practical applications. In this talk we discuss approximation algorithms for the prize-collecting version of the Traveling Salesman Problem (TSP) and some of its generalizations. Zoom room information: https://us06web.zoom.us/j/84906984159?pwd=BCWaIbXBuku3A5I84zNg9mHFxVZjXD.1 Meeting ID: 849 0698 4159 Passcode: 362880 Venue: Niavaran, Le ... 15:30 - 17:00 Geometry and Topology Weekly Seminar The Pants Graph and the Teichmuller Space School MATHEMATICS The pants graph of a compact orientable surface S, introduced by Hatcher and Thurston, is a simplicial graph whose vertices are maximal essential multicurves on S and whose edges correspond to certain local moves on multicurves. The importance of the pants graph comes from a theorem of Brock showing that the pants graph is a good combinatorial model for the Teichmuller space with the Wiel-Petersson metric, which is the space of hyperbolic metrics on S up to isotopy. In joint work with Marc Lackenby, we give upper bounds for distance in the pants graph and derive applications for distance in the Teichmuller space and also for volumes of hyper ... 17:30 - 19:00 Algebraic Geometry Biweekly Webinar Tyurin degenerations, Relative Lagrangian foliations and categorification of DT invariants School MATHEMATICS We discuss construction of a derived Lagrangian intersection theory of moduli spaces of perfect complexes, with support on divisors on compact Calabi Yau threefolds. Our goal is to compute deformation invariants associated to a fixed linear system of divisors in CY3. We apply a Tyurin degeneration of the CY3 into a normal-crossing singular variety composed of Fano threefolds meeting along their anti-canonical divisor. We show that the moduli space over the Fano 4 fold given by total space of degeneration family satisfies a relative Lagrangian foliation structure which leads to realizing the moduli space as derived critical locus of a global ( ... |