Your math-fu is simpler than mine.
That's the condition I was aiming to describe, yes. I was looking for a formula that would pick up posts that had a large proportion of downvotes, but were popular enough to imply a well-fought argument rather than a post that was simply bad.
It seems that if you look at the column on the right of the page, you can see upvotes and downvotes separately for recent posts. The same [n, m] format is displayed for recent comments, but it doesn't seem to actually sync with the score displaying on the comment. This feature only seems available on the sidebar: looking at the actual comment or post doesn't give you this information.
Thanks, whoever did this!