Speaker: Alessandro Chiodo (IMJ-PRG)

Title: Genus-one double ramification cycles via Picard functors

Abstract: The Double Ramification (DR) cycle parametrizes, within the moduli space of smooth curves, the locus of curves paired with a principal divisor. Gromov-Witten theory is needed to define this cycle within the moduli space of stable curves. Using this definition and localization techniques, Janda, Pixton, Pandharipande and Zvonkine provide a surprising relation expressing the DR cycle using moduli of roots of the structure sheaf. In this talk we provide a definition of the DR cycle on the moduli space of smooth curves using David Holmes description of NĂ©ron models of the Jaconian over moduli of curves of dimension greater than one. We compute this cycle in genus one and match Janda-Pandharipande-Pixton-Zvonkine formula. (This is work in collaboration with David Holmes.)