Seminar

Following last week's discussion of p-divisible groups over commutative ring spectra, we'll define formal groups over commutative ring spectra. One key example is the Quillen formal group associated to a complex oriented ring spectrum. We'll introduce the idea of an orientation of a formal group, which amounts to an isomorphism with the associated Quillen formal group. This will allow us to state the new construction of Morava E-theory -- it is the object representing oriented deformations of a height n formal group over a perfect field.