Recursion for twisted descendants and characteristic numbers of rational curves
نویسنده
چکیده
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 Gromov-Witten 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.
منابع مشابه
Characteristic numbers of rational curves with cusp or prescribed triple contact Joachim Kock
This note pursues the techniques of modified psi classes on the stack of stable maps (cf. [Graber-Kock-Pandharipande]) to give concise solutions to the characteristic number problem of rational curves in P2 or P1×P1 with a cusp or a prescribed triple contact. The classes of such loci are computed in terms of modified psi classes, diagonal classes, and certain codimension-2 boundary classes. Via...
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