The mini-symposium “Absolute Arithmetic and -Geometry” is part of the official scientific programme of the prestigious quadrennial European Congress of Mathematics (July 2-7 2012, Krakow, Poland). This conference is widely considered to be one of the most important mathematical gatherings around. The general character of the programme provides attendees with a unique chance of an [...]

Here is the recently published paper “The hyperring of adèle classes” (by Connes and Consani). ConnesConsani2011

Last time, we tried to generalize the Connes-Consani approach to the noncommutative world but didn’t specify what we meant by noncommutative varieties or schemes and how they were related to Grothendieck’s dessins d’enfants. That’s what we will do today.

It is perhaps surprising that Alain Connes and Katia Consani, two icons of noncommutative geometry, restrict themselves to define commutative algebraic geometry over the field with one element. Remains the fact that their approach screams for a noncommutative extension.

Grothendieck’s anabelian geometry is an example of noncommutative F_un geometry. Javier starts this series with ramblings on how the folklore about F_un can be used to relate linear and permutation representations of finite groups.