Seminar in Real and Complex Geometry

Thursday, October 21, 2021, 16:00-17:30, online (via zoom)




Erwan Brugallé
(Université de Nantes)

Euler characteristic and signature of real semi-stable degenerations


Abstract
             

It is interesting to compare the Euler characteristic of the real part of a real algebraic variety to the signature of its complex part. For example, a theorem by Itenberg and Bertrand states that both quantities are equal for "primitive T-hypersurfaces". After defining these latter, I will give a motivic proof of this theorem via the motivic nearby fiber of a real semi-stable degeneration. This proof extends in particular the original statement by Itenberg and Bertrand to non-singular tropical varieties.