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The Abelianisation of the real plane Cremona group

Le : 13/11/2015 14h00
Par : Susanna Zimmermann (Bâle)
Lieu : I 001
Lien web :
Résumé : The Cremona group of the complex plane contains many normal subgroups, all of which are of infinite index, it has no non-trivial normal subgroups containing non-trivial elements of degree 1 or 2, and it is perfect. What about the Cremona group of the real plane? We will see that the above properties do not hold for the real plane Cremona group, for instance there are uncountably many normal subgroups of finite index and the normal subgroup generated by a countable number of elements is a proper subgroup. These are direct consequences of the structure of the Abelianisation of the Cremona group, which I will present in this talk.