# Spring 2011 Symplectic Geometry Seminar

## Spring 2011

date | speaker | title | host(s) |
---|---|---|---|

Feb. 9th | Jie Zhao | Witten's Proof of Morse Inequality | |

Feb. 16th | Jie Zhao | Witten's Proof of Morse Inequality (continued) | |

Mar. 2nd | Rui Wang | A simpler proof of the generical existence of nondegenerate contact forms (rescheduled) | |

Mar 9th | Dongning Wang | On orbifold fibered over a manifold | |

Mar 16th | Erkao Bao | Fredholm index in SFT. | |

Apr 13th | Jaeho | Enumerative tropical geometry in R^2. | |

Apr 20th | Jaeho | Enumerative tropical geometry in R^2(continued). | |

May 11th | Lino | Quantum A-infinity Algebras. |

## Abstracts

**Dongning Wang** *On orbifold fibered over manifold*

As an analogue of fiber bundle over manifold, there is a definition of orbibundle over orbifold where the structure group of the total space is required to be the same as the base orbifold. This requirement can be removed and we will get a more general definition of orbibundle. In this talk, I will focus on a special case of the generalization: the base is a manifold. I call this case "orbifold fibered over manifold". A particular case of orbifold fibered over manifold where the base is a sphere will be use to definite orbifold Seidel representation. Seidel representation is a group morphism from [math]\displaystyle{ \pi_1(Ham(M,\omega)) }[/math] to the multiplication group of the quantum cohomology ring [math]\displaystyle{ QH^*(M,\omega) }[/math]. It can be used to compute quantum cohomology ring of Fano toric manifolds. Orbifold Seidel representation generalize the theory to orbifold case, and can be used to compute the orbifold quantum cohomology ring of a large class of Fano toric orbifolds. This is a joint work with Hsian-Hua Tseng.