Thank you Canoedogs for the Boing Boing alert.

The paper
http://www.mathstat.uottawa.ca/~rsmith/Zombies.pdf
is an interesting read.
I have not worked all the way through it yet. So far not bad at all. (Yes, Zombies are a fine metaphor. I have no problem with that)
I am sure I will question some of their assumptions, but it is a good example of the math problems and is quite clearly worked out.

edit: I am especially disappointed at how little effect quarranteening Zombies seems to have, and that is without any loose vectors.