EXTENDING THE DOUBLE RAMIFICATION CYCLE BY RESOLVING THE ABEL-JACOBI MAP. (20th January 2021)

• Record Type: Journal Article
• Authors: Holmes, David
• Is Part Of: Journal of the Institute of Mathematics of Jussieu. Volume 20:Number 1(2021)
• Page Start: 331
• Page End: 359
• Publication Date: 2021-01-20
• Subjects: curves, -- jacobians, -- cycles; 14H10, -- 14H40; Mathematics -- Periodicals; 510.5
• DOI: 10.1017/S1474748019000252
• Languages: English
• ISSNs: 1474-7480

Abstract

Abstract: Over the moduli space of smooth curves, the double ramification cycle can be defined by pulling back the unit section of the universal jacobian along the Abel–Jacobi map. This breaks down over the boundary since the Abel–Jacobi map fails to extend. We construct a 'universal' resolution of the Abel–Jacobi map, and thereby extend the double ramification cycle to the whole of the moduli of stable curves. In the non-twisted case, we show that our extension coincides with the cycle constructed by Li, Graber, Vakil via a virtual fundamental class on a space of rubber maps.