## Intersection Theory of the Tropical Moduli Spaces of Curves

- Tropical geometry is a very new mathematical domain. The appearance of tropical geometry was motivated by its deep relations to other mathematical branches. These include algebraic geometry, symplectic geometry, complex analysis, combinatorics and mathematical biology. In this work we see some more relations between algebraic geometry and tropical geometry. Our aim is to prove a one-to-one correspondence between the divisor classes on the moduli space of n-pointed rational stable curves and the divisors of the moduli space of n-pointed abstract tropical curves. Thus we state some results of the algebraic case first. In algebraic geometry these moduli spaces are well understood. In particular, the group of divisor classes is calculated by S. Keel. We recall the needed results in chapter one. For the proof of the correspondence we use some results of toric geometry. Further we want to show an equality of the Chow groups of a special toric variety and the algebraic moduli space. Thus we state some results of the toric geometry as well. This thesis tries to discover some connection between algebraic and tropical geometry. Thus we also need the corresponding tropical objects to the algebraic objects. Therefore we give some necessary definitions such as fan, tropical fan, morphisms between tropical fans, divisors or the topical moduli space of all n-marked tropical curves. Since we need it, we show that the tropical moduli space can be embedded as a tropical fan. After this preparatory work we prove that the group of divisor classes in v classical algebraic geometry has it equivalence in tropical geometry. For this it is useful to give a map from the group of divisor classes of the algebraic moduli space to the group of divisors of the tropical moduli space. Our aim is to prove the bijectivity of this map in chapter three. On the way we discover a deep connection between the algebraic moduli space and the toric variety given by the tropical fan of the tropical moduli space.

Author: | Matthias Herold |
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URN (permanent link): | urn:nbn:de:hbz:386-kluedo-32760 |

Advisor: | Andreas Gathmann |

Document Type: | Diploma Thesis |

Language of publication: | English |

Publication Date: | 2012/09/29 |

Year of Publication: | 2007 |

Publishing Institute: | Technische Universität Kaiserslautern |

Granting Institute: | Technische Universität Kaiserslautern |

Date of the Publication (Server): | 2012/10/01 |

Number of page: | 49 |

Faculties / Organisational entities: | Fachbereich Mathematik |

DDC-Cassification: | 5 Naturwissenschaften und Mathematik / 510 Mathematik |

MSC-Classification (mathematics): | 14-XX ALGEBRAIC GEOMETRY / 14Txx Tropical geometry [See also 12K10, 14M25, 14N10, 52B20] / 14T05 Tropical geometry [See also 12K10, 14M25, 14N10, 52B20] |

Licence (German): | Standard gemäß KLUEDO-Leitlinien vom 10.09.2012 |