Article - postprint
We compute the local Gromov-Witten invariants of the "closed vertex", that is, a configuration of three rational curves meeting in a single triple point in a Calabi-Yau threefold. The method is to express the local invariants of the vertex in terms of ordinary Gromov-Witten invariants of a certain blowup of CP^3 and then to compute those invariants via the geometry of the Cremona transformation.
© 2005 Journal of Algebraic Geometry
J. Bryan, D. Karp, The closed topological vertex via the Cremona transform, Journal of Algebraic Geometry, 14, 529–542 (2005). arXiv version math.AG/0311208