Dear Warren, for the top-down approach to create a party list, I would define "proportionality" as follows:
Suppose place 1 to (n-1) have already been filled. Suppose A(i) (with i = 1,...,(n-1)) is the candidate of place i. Suppose we want to fill the n-th place. Suppose it is possible to find a candidate B such that the set {A(1),...,A(n-1),B} satisfies Droop proportionality for n seats. Then the n-th seat goes to a candidate B such that the set {A(1),...,A(n-1),B} satisfies Droop proportionality for n seats. Markus Schulze ---- Election-Methods mailing list - see http://electorama.com/em for list info