Yuan-Pin LeeDepartment of Mathematics, University of Utah, Salt Lake City, Utah, 84112Feng QuDepartment of Mathematics, University of Utah, Salt Lake City, Utah, 84112
We give an effective algorithm to compute the Euler characteristics χ(\mbar_{1,n}, \otimes_{i=1}^n L_i^{d_i}). In addition, we give a simple proof of Pandharipande's vanishing theorem H^j (\mbar_{0,n}, \otimes_{i=1}^n L_i^{d_i})=0 for j≥1,di≥0.
Yuan-Pin LeeDepartment of Mathematics, University of Utah, Salt Lake City, Utah, 84112Hui-Wen LinTaida Institute of Mathematical Sciences (TIMS), National Taiwan University, Taipei 106Chin-Lung WangCenter for Advanced Study in Theoretical Sciences, National Taiwan University, Taipei 106
This is the second of a sequence of papers proving the quantum invariance for ordinary flops over an arbitrary smooth base. In this paper, we complete the proof of the invariance of the big quantum rings under ordinary flops of splitting type.
To achieve that, several new ingredients are introduced. One is a quantum Leray--Hirsch theorem for the local model (a certain toric bundle) which extends the quantum D module of Dubrovin connection on the base by a Picard--Fuchs system of the toric fibers.
Nonsplit flops as well as further applications of the quantum Leray--Hirsch theorem will be discussed in subsequent papers. In particular, a quantum splitting principle is developed in Part III which reduces the general ordinary flops to the split case solved here.
Yuan-Pin LeeDepartment of Mathematics, University of Utah, Salt Lake City, Utah, 84112Hui-Wen LinTaida Institute of Mathematical Sciences (TIMS), National Taiwan University, Taipei 106Feng QuInternational Center for Mathematical Research (BICMR), Beijing (Peking) University, Beijing 100871, PR ChinaChin-Lung WangCenter for Advanced Study in Theoretical Sciences, National Taiwan University, Taipei 106
The paper is Part III of our ongoing project to study a case of Crepant Transformation Conjecture: K-equivalence Conjecture for ordinary flops. In this paper we prove the invariance of quantum rings for general ordinary flops, whose local models are certain non-split toric bundles over arbitrary smooth base. An essential ingredient in the proof is a quantum splitting principle, which reduces a statement in Gromov--Witten theory on non-split bundles to the case of split bundles.
Nathan PriddisInstitut für Algebraische Geometrie, Universität Hannover, D-30060 HannoverYuan-Pin LeeDepartment of Mathematics, University of Utah, Salt Lake City, UT 84112Mark ShoemakerDepartment of Mathematics, Colorado State University Fort Collins, CO 80523
We establish a new relationship (the MLK correspondence) between twisted FJRW theory and local Gromov-Witten theory in all genera. As a consequence, we show that the Landau-Ginzburg/Calabi-Yau correspondence is implied by the crepant transformation conjecture for Fermat type in genus zero. We use this to then prove the Landau-Ginzburg/Calabi-Yau correspondence for Fermat type, generalizing the results of A. Chiodo and Y. Ruan.
Yuan-Pin LeeDepartment of Mathematics, University of Utah, Salt Lake City, Utah, 84112Hui-Wen LinTaida Institute of Mathematical Sciences (TIMS), National Taiwan University, Taipei 106Chin-Lung WangTaida Institute of Mathematical Sciences (TIMS), National Taiwan University, Taipei 106
For projective conifold transitions between Calabi-Yau threefolds X and Y, with X close to Y in the moduli, we show that the combined information provided by the A model (Gromov--Witten theory in all genera) and B model (variation of Hodge structures) on X, linked along the vanishing cycles, determines the corresponding combined information on Y. Similar result holds in the reverse direction when linked with the exceptional curves.