Date | Jul 19, 2022 |
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Speaker | Pablo Portilla cuadrado |

Dept. | University of Lille |

Room | 129-406 |

Time | 10:30-13:00 |

In this talk, we study the nilpotent part of a pseudo-periodic automorphism of a real oriented

surface with boundary. We associate a quadratic form Q defined on the first homology group of the surface.

Using some techniques from mapping class group theory, we prove that a related form is positive

definite under some conditions that are always satisfied for monodromies of Milnor fibers of germs of curves on

normal surface singularities. Moreover, the form Q is computable in terms of the dual resolution or semistable reduction graph.

Numerical invariants associated with Q are able to distinguish plane curve singularities with different topological

types but same spectral pairs. This is a joint work with L. Alanís, E. Artal, C. Bonatti, X. Gómez-Mont and M. González Villa.

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