Title: Boundary divisors in the stable pair compactification of the moduli space of Horikawa surfaces, Speaker(s): Luca Schaffler, Roma 3, Date and time: 4 May 2022, 14:30 (Europe/Rome), Lecture series: Algebraic and Arithmetic Geometry Seminar, Venue: Dipartimento di Matematica (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/71 Abstract -------- Smooth minimal surfaces of general type with $K^2=1$, $p_g=2$, and $q=0$ constitute a fundamental example in the geography of algebraic surfaces, and the 28-dimensional moduli space $M$ of their canonical models admits a geometric and modular compactification $\overline{M}$ by stable surfaces. Franciosi-Pardini-Rollenske classified the Gorenstein stable degenerations parametrized by it, and jointly with Rana they determined boundary divisors parametrizing irreducible stable surfaces with a unique T-singularity. In this talk, we continue with the investigation of the boundary of $\overline{M}$ constructing eight new irreducible boundary divisors parametrizing reducible surfaces. Additionally, we study the relation with the GIT compactification of $M$ and the Hodge theory of the degenerate surfaces that the eight divisors parametrize. This is joint work in progress with Patricio Gallardo, Gregory Pearlstein, and Zheng Zhang. -- Indico :: Email Notifier https://events.dm.unipi.it/e/71