Is (Google) PageRank invalidated by this econ. paper from 1940s?


Some early versions of PageRank are discussed the PageRank: Standing on the shoulders of giants

My question is whether any of the prior art mentioned in the article would be sufficient to invalidate Google's Patent 7,269,587 on the PageRank algorithm?

It seems to have the same premise as Google's PageRank.

Patent: 7,269,587

Inventor: Larry Page

Assigned to: Stanford University (now licensed exclusively to Google)

Priority date: Jan 10, 1997

The main independent claim is as follows:

  1. A computer implemented method for calculating an importance rank for N linked nodes of a linked database, the method comprising:

    • (a) selecting an initial N-dimensional vector p0, wherein each component of p0 represents a probability that a user will start at a given node, wherein each node of the N linked nodes is a computer-readable document containing information;

    • (b) computing an approximation pn to a steady-state probability p∞, wherein each component of p∞ represents a probability that the user will randomly end up at a particular node after following a number of forward links, in accordance with the equation pn=Anp0, where A is an N×N transition probability matrix having elements A[i][j] representing a probability of moving from node i to node j; and

    • (c) determining a rank r[k] for a node k from a kth component of pn, wherein r[k] represents an importance of the information contained in node k.

Jonathan Howard

Posted 2013-08-26T05:03:36.687

Reputation: 23

Jonathan, AskPatents is an online service in Q&A format where users help find prior art on US Patent Applications and US Patents and ask questions about the US Patent process. It is difficult for the community at Ask Patents to answer your question because you have not provided a US Patent Number. Feel free to modify your question and resubmit. Please see the [faq] for more information about which topics are on topic. Sorry for any confusion. – Micah Siegel – 2013-08-26T05:53:03.750

Added the US patent number. – Jonathan Howard – 2013-08-26T15:03:35.193

Jonathan, The question has been reopened with more information about the patent number you cite. Thanks for participating in Ask Patents! – Micah Siegel – 2013-08-26T18:33:44.247



To show something as "not new" there is no extra weight given to something really old. If it proceeds the priority date by a day, that's enough. If you look at the '587 patent you will see that most of the things mentioned in the article are cited on the face of the patent. That means they were taken into consideration by the examiner. You might note that the author of the article says that Kienberg's work was "just a few years earlier" than Google's. From what is cited on the patent that seems in error. His paper may have been before their paper but it was after their patent priority filing date. Jan 1997 vs May 1997 from what I see.


To go back to an economics paper on inputs and outputs of goods and services from one region to another that has nothing to do with citations and to see something, that like page rank, that is also calculated iteratively seems like using hind sight. Once you have the page rank invention you can go back and find things that might have hinted at the solution. You can only do that after knowing the solution. Not allowed.

George White

Posted 2013-08-26T05:03:36.687

Reputation: 21 648