Page is a not externally linkable
- Google
-- Google News Archive
---- Why AOL and MSN execs need to be mathematicians

doc_z - 8:04 pm on Apr 2, 2004 (gmt 0)

 And these are based on DMOZ subtopic-based conditioning.

It seems that you're referring to Haveliwala's papers. His ODP biasing ansatz is not only dealing with topic-sensitive PageRank but also with an authority system, i.e. most entries of the PageRank vector are zero independent from the topic. However, there is no need to mix these different issues. As long as one is only interested in topic-sensitive PageRank and not in an authority system, you can determine the topic from on page factors. Therefore, ODP might be important for an authority system but not for purely topic-sensitive PageRank.

By the way, even in Haveliwala's and other Stanford papers there are no recursive definitions just recursive methods to solve linear equations.

Here is a brief, rough overview for those who are interested in this topic:
- The standard (original) PR algorithm uses a single constant PageRank vector, i.e. the self-contribution of each page is the same. (In the random surfer model this corresponds to a uniformly distributed probability to be teleported to a page.)
- In the authority system only selected sources have a weight, i.e. most of the entries in the PR vector are zero. (Therefore, one is only teleported to a selected set of pages.)
- Topic sensitive PageRank uses a set of vectors. (The transition probability is topic dependent.)

 I'm not here to give people math lessons

Before giving math lessons you should at least avoid such mistakes as calling a simple set of linear equations 'recursive'.

Thread source:: http://www.webmasterworld.com/google_archive/23034.htm
Brought to you by WebmasterWorld: http://www.webmasterworld.com