

Scientist Finds PageRank-Type Algorithm from the 1940s - Peteris
http://www.technologyreview.com/view/417529/scientist-finds-pagerank-type-algorithm-from-the-1940s/

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frisco
What a silly article. PageRank is based on eigenvector centrality[1], which is
one of a number of well-understood centrality measures that have been around
for a long time. Google's innovation was noticing the importance of the link
structure of the internet and knowing to apply EC to it - not inventing the
graph theory underlying EC.

Edit: and knowing to apply EC to that graph structure.

[1]
[http://en.wikipedia.org/wiki/Centrality](http://en.wikipedia.org/wiki/Centrality)

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nullc
What they patented, however, is more broad than that still:

1\. A computer implemented method of scoring a plurality of linked documents,
comprising: obtaining a plurality of documents, at least some of the documents
being linked documents, at least some of the documents being linking
documents, and at least some of the documents being both linked documents and
linking documents, each of the linked documents being pointed to by a link in
one or more of the linking documents; assigning a score to each of the linked
documents based on scores of the one or more linking documents and processing
the linked documents according to their scores.

~~~
6ren
Patent claims usually begin with the broadest claim possible, then narrow it
in following claims. If the first is found invalid, the other claims may still
succeed. Thus, it makes no sense for the first claim to be certain to stand on
its own; strategically, it _should_ be over-broad.

From a computer science/mathematics point of view, this is also a convenient
way to factor out commonalities of several claims, instead of duplicating them
_ad nauseam_. For example, in the PageRank patent, claim 1 is immediately
followed by six dependent claims giving further detail on it (as do ten other
claims scattered through the rest):
[https://www.google.com/patents/US6285999](https://www.google.com/patents/US6285999)

Thus, it is inaccurate to treat the first claim as "what they patented".

~~~
throwawaykf02
While it's true that the independent claims try to be as broad as possible and
dependent claims narrow them down, each claim is still evaluated -- and must
be valid -- on an individual basis. And if infringement of a patent is to be
determined, you'd start with the independent claims and work your way down, as
those have the broadest scope.

So, yes, it does make sense to say that the patent claims what nullc quoted.
It's only slightly inaccurate in that the patent also claims a lot more, but
the independent claims define the broadest scope.

~~~
6ren
Oh dear, you and nullc are right, and I am wrong. My apologies. This patent
was granted, and so they do have a patent for claim 1 (and also for the other
claims). I was confusing it with a patent application.

It's surprising to me that even the cursory prior art search of examination
didn't turn up this idea, since it's so simple, doesn't use any of the meat of
the invention described, and the idea of ranking by citation was well-known,
e.g. for academic papers. I think applying that to hypertext links is clever
and insightful... but not patent-worthy (like many other patents). Upon
litigation, I think claim 1 might not stand. But regardless, the patent was
granted, so they do have a patent on claim 1.

Thanks for taking the time to correct me.

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Houshalter
I'm really curious how on Earth they tracked all these down. Imagine how many
obscure papers were published they didn't look through that had the same idea.

>One important question is: what is the value of each sector when they are so
tightly integrated? Leontief’s answer was to develop an iterative method of
valuing each sector based on the importance of the sectors that supply it.

That's actually pretty interesting. But I think in economics a circular graph
doesn't really make sense, does it? It's more two ways with one person trading
with another person (with any number of intermediate nodes.)

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jimhefferon
> how on Earth they tracked all these down

I don't know that work done by a famous, and Nobel prize-winning, author
really qualifies as "tracking down."

This is a superficial article and I have not read the underlying paper, but in
the article it is unclear how wide was the literature search.

~~~
Houshalter
Yes, it was a famous example, which made it easier to find. My point is think
of all the obscure papers published that also had that idea.

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amerika_blog
Ah, the innovation of our age... isn't innovation after all.

~~~
blauwbilgorgel
Surely this is innovation when applied to a new domain (ranking websites).
Also Google never stopped innovating PageRank and other ranking techniques.

PG applying Bayes' theorem to e-mail spam was innovative.

If we get very loose with our definition of algorithm, one could even say that
ants implemented the first PageRank-like algorithm, when they ranked sources
of food, using pheromone trails.

~~~
walid
Well I haven't read the actual page ranking patent but apply existing math to
solve a problem is not innovation.

However your example about ants is very true. Ants should be the patent
holders of page ranking. But that also means the patent should have already
expired a long time ago.

