Refined Class Number Formulas and Kolyvagin Systems

We use the theory of Kolyvagin systems to prove (most of) a refined class number formula conjectured by Darmon. We show that for every odd prime p, each side of Darmon’s conjectured formula (indexed by positive integers n) is “almost” a p-adic Kolyvagin system as n varies. Using the fact that the space of Kolyvagin systems is free of rank one over Zp, we show that Darmon’s formula for arbitrary n follows from the case n = 1, which in turn follows from classical formulas.