Focusing Page Rank by limiting content?

Analytically - Can new pages hurt?

This is a question that's puzzled me for awhile and which I thought I would put to a forum that I'm now active on: John Scott's V7N webmasters forum.

Before I get to the question about content and whether too much defocuses googlejuice, let's talk about his forum. He has some good quality content (his seo intro is fabulous). The forum has a policy of not only ranking contributors by number of posts (junior, senior, emeritus etc) which is addictive but he provides some perks along the way. The most visible one is that at 50 posts, you can have live links in your signature. Of course, there are oodles of people posting silly short comments to get their post count up....

I added this math seo puzzler on the back of this discussion: "Does adding new content without adding new links hurt your search engine position....."

My post.....I'd like to take this question towards the mathematical and away from the simplistic "go get some links".....

Assume that I have a 5 page site on widgets. Each page talks about different widgets. Say A Widgets, B widgets... right up to the 5th letter. But all my links come into my home page which is the A widget page.

If I add a sixth page but without adding any links, does that hurt my positioning on google for B Widgets?

Or, does adding new pages, while keeping the link count constant, mathematically reduce the PageRank (in the truest sense of the word) of my existing pages?

I've read extensively on this point and have learned about dampeners and matrices and such but nobody seems to deal with this question directly.The math suggests that the page rank from the total links in cannot be used over and over again for any given number of (even relevant) keywords. But then, why doesn't anyone discuss how to optimize from this question of having the optimal amount of content for the incoming links?

In my case, this is an academic but puzzling case since I am busy adding content (quality) and links as fast as I can to: Time4Learning.com. Still, I wonder if rather than going for learning games, Educational Games , and teaching games, I should make more choices....