I'm not sure exactly what you are referring to...could you clarify your question a bit?
Do you mean how do links in a PDF influence the PageRank of the linking site. If so, I don't think that google follows links in PDF's but this is not an issue I have ever run into.
capability appeared in Acrobat version 7, and it is not available in some of the other software that can generate a PDF file. HTML links to particular pages are formed by using the "#" fragment identifier which has not historically been involved in PR calculations.
Even if there are some links inside the PDF documents, I really wonder how effective or strong they could be in terms of being counted as backlinks, let alone boosting the PR of the recipients.