Quadratic Enumerative Invariants and Local Contributions in Algebraic Geometry

Explore a mathematical lecture that delves into quadratic enumerative geometry and its extension of classical enumerative geometry, focusing on how answers to enumerative questions exist as classes of quadratic forms within the Grothendieck-Witt ring GW(k). Learn about computing quadratic enumerative invariants using Marc Levine's localization methods, with specific attention to counting lines on smooth cubic surfaces. Discover the geometric significance of these counts, including how individual lines on smooth cubic surfaces contribute elements to GW(k), and understand Kass-Wickelgren's geometric interpretation that generalizes Segre's classification of real lines. Examine the extension of these concepts to lines of hypersurfaces of degree 2n − 1 in Pn+1, featuring collaborative work with Felipe Espreafico and Stephen McKean. Recorded during the thematic meeting "Motivic homotopy in interaction" at the Centre International de Rencontres Mathématiques in Marseille, France, this hour-long presentation includes chapter markers, keywords, and comprehensive mathematical classifications for enhanced learning accessibility.