Simple answer is no. Google once published a formula that they used to calculate PR. It's probably not used any more but consensus is that it's not a bad starting point. Here 'tis: PR(A) = (1-d) + d (PR(T1)/C(T1) + ... + PR(Tn)/C(Tn)) Where PR(A) is the PageRank of Page A (the one we want to work out). D is a dampening factor. Nominally this is set to 0.85 PR(T1) is the PageRank of a site pointing to Page A C(T1) is the number of links off that page PR(Tn)/C(Tn) means we do that for each page pointing to Page A Yikes! So for those of you that aren't mathematicians, heres the low-down on that formula – you cant simply calculate PageRank in one go like that. To calculate the PageRank of Page A you'd need to know the PageRank of all the pages pointing to Page A. Their PageRanks would in part be due to Page A pointing to them or some other site that points to them! What a silly formula. What it does tell us is one very important thing about the PageRank of any page… So by having 8 links form one page to another is the same net result as having one. BUT.....if you have a link to one other page as well as the 8 to the other, then the page with one link only only gets 1/9th the weight as if you had only 1 link to the other page when it would get hald the weight.
Those formulas really made my head hurts. Although I understood a little bit of it. Anyways, what about signature links that shows up on a single page?