

Harvard computer scientist Leslie Valiant wins Turing Award  - alphadoggs
http://www.networkworld.com/news/2011/030911-valiant-turing-award.html?hpg1=bn

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kanak
Prof. Leslie Valiant has done awesome work in complexity theory. Among other
things, he:

* introduced the notion of #P [1]. Replacing the "Is there any ..." question in an NP problem with "How many ... " makes a problem #P e.g. "Is there any subset in this list of integers that adds up to zero" is an NP problem, "How many subsets add up to zero" is a #P problem. This class also includes the problem of doing exact inference in a general graphical model.

* introduced the "Probably Approximately Correct" notion in machine learning for analyzing various learning techniques. [2]

* with Vijay Vazirani, stated & proved the Valiant-Vazirani theorem [3] that, in essence, showed that the intractability of NP problems is not related to the wide variation in possible solutions for the problem. E.g. the Satisfiability problem could have anywhere from zero to exponentially many solutions, but this variance is not the reason it is hard.

[1]
[http://qwiki.stanford.edu/index.php/Complexity_Zoo:Symbols#s...](http://qwiki.stanford.edu/index.php/Complexity_Zoo:Symbols#sharpp)

[2] <http://web.mit.edu/6.435/www/Valiant84.pdf>

[3]
[http://www.cs.princeton.edu/courses/archive/fall05/cos528/ha...](http://www.cs.princeton.edu/courses/archive/fall05/cos528/handouts/NP_is_as.pdf)

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Q6T46nT668w6i3m
* The algorithm that shares his namesake, an extension of the CYK algorithm (a parsing algorithm for context-free grammars), is the fastest known.[1]

[1] Leslie G. Valiant. General context-free recognition in less than cubic
time. Journal of Computer and System Sciences, 10:2 (1975), 308–314.

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mmelin
Note that the Turing Award != Turing Test, which was my initial (excited)
thought.

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bartonfink
That a Harvard professor was able to convince an observer he was, in fact,
human?

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kemiller
He was my undergrad advisor, and I have to say, he never convinced me.

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kenjackson
Anyone want to wager on the next three Turing Award winners?

My nominations:

Peter Shor

Maurice Herlihy

Richard Stallman

Mario Szegedy

Bill Dally

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pgbovine
_Richard Stallman_

hmmm, i think Turing Awards are more biased towards theoretical contributions
to CS (even for systems people). Although Stallman has made great
contributions to the field of computing, he isn't an academic CS researcher,
so he might not be in the running :/

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kenjackson
I thought about that too, so I had checked what ACM said:

"It is given to an individual selected for contributions of a technical nature
made to the computing community. The contributions should be of lasting and
major technical importance to the computer field"

I think his work with GNU has been one of the most important technical
contributions to the community we've seen.

On a non-technical note, his push for free software has also been incredibly
influential for the community. While I disagree with a lot of ideology and in
particular the ideology behind the GPL personally, I think the world is
generally better for it.

