ABSTRACT
Let us start by supposing that —* is a notion of causation. We will agree that there is an underlying causal field, Q and F. We will also agree that —* is a relation between factors defined on that field and factors in a collection G This means that for some pairs (f,g) of factors with f€ HP and ge G, the relationship holds, written f-> g, and for others it does not, written f'—> g. We will say that —> is on OF to G.
