Séance Séminaire

Séminaire des Doctorant·e·s

mercredi 15 janvier 2020 à 15h - Salle 109

Joost Nuiten (IMAG)

The space of formal groups

A formal group (of rank 1) is a formal power series in two variables F(x, y) satisfying the usual axioms of a commutative group. The simplest example of a formal group is the additive one F(x, y)=x+y, but there are many others. I will give some examples and then discuss a picture of the collection of such formal groups, due to Lazard. If time permits, I would like to briefly advertise the relevance of this picture (the `chromatic picture') to algebraic topology.