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Universität Augsburg
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Universität Augsburg
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Professor Dr. Diarmuid Crowley
University of Melbourne
spricht am
Donnerstag, 22. Juni 2017
um
12:15 Uhr
im
Raum 2004 (L1)
über das Thema:
| Abstract: |
| A classical result of Novikov gives the additivity of the signature when two manifolds with boundary are glued together along a diffeomorphism. In this talk we consider the (non)-additivity of the A-hat genus when two spin 8-manifolds with boundary are glued together along a spin diffeomorphism. We identify an invariant of the boundary, called its reactivity, which controls the additivity of the A-hat genus in this setting. The reactivity of a 7-manifold M with G_2 structure is used in the definition a secondary invariant of the G_2-structure called the \xi-invariant. The \xi-invariant features in a complete classification of 2-connected 7-manifolds with G_2-structure. This is part of joint work with Sebastian Goette and Johannes Nordström. |
| Hierzu ergeht herzliche Einladung. |
| Prof. Dr. Wolfgang Steimle |