This is derived in Section 3 along with a new proof of Morgan's theorem.
In Section 2 the reader will be reminded of some important properties of Bernoulli numbers, and some auxiliary results will be quoted or derived.
However, we know of no way of deriving one theory directly from the other.
Here we consider a dual variational formulation which can be derived similarly to that for the sandpile model.
This term derives from “quiver'', a notion used in representation theory of algebras.
Most of the proofs in this paper derive from those given by Fox for geometrically finite maps in [F].