The nature of monetary arrangements is often discussed without any reference to its detailed construction. We present a graph representation that allows for a clear understanding of modern monetary systems. First, we show that systems based on commodity money are incompatible with credit. We...

A graph representation of the financial relations in a given monetary structure is proposed. It is argued that the graph of debt-liability relations is naturally organized and simplified into a tree structure, around banks and a central bank. Indeed, this optimal graph allows to perform payments...