Recursion for twisted descendants and characteristic numbers of rational curves
Abstract
On a space of stable maps, the psi classes are modified by subtracting certain boundary divisors. The top products of modified psi classes, usual psi classes, and classes pulled back along the evaluation maps are called twisted descendants; it is shown that in genus 0, they admit a complete recursion and are determined by the GromovWitten invariants. One motivation for this construction is that all characteristic numbers (of rational curves) can be interpreted as twisted descendants; this is explained in the second part, using pointed tangency classes. As an example, some of Schubert's numbers of twisted cubics are verified.
 Publication:

arXiv Mathematics eprints
 Pub Date:
 February 1999
 arXiv:
 arXiv:math/9902021
 Bibcode:
 1999math......2021K
 Keywords:

 Mathematics  Algebraic Geometry;
 14N10;
 14H10
 EPrint:
 20 pages, LaTeX, uses Paul Taylor's commutative diagrams package