Computation of the classifying ring of formal modules

Abstract

In this paper, we develop general machinery for computing the classifying ring $L^A$ of one-dimensional formal A-modules, for various commutative rings A. We then apply the machinery to obtain calculations of $L^A$ for various number rings and cyclic group rings A. This includes the first full calculations of the ring $L^A$ in cases in which it fails to be a polynomial algebra. We also derive consequences for the solvability of some lifting and extension problems.