Posted on **08/14/2006 11:26:41 PM PDT** by **neverdem**

Grisha Perelman, where are you?

Three years ago, a Russian mathematician by the name of Grigory Perelman, a k a Grisha, in St. Petersburg, announced that he had solved a famous and intractable mathematical problem, known as the Poincaré conjecture, about the nature of space.

After posting a few short papers on the Internet and making a whirlwind lecture tour of the United States, Dr. Perelman disappeared back into the Russian woods in the spring of 2003, leaving the world’s mathematicians to pick up the pieces and decide if he was right.

Now they say they have finished his work, and the evidence is circulating among scholars in the form of three book-length papers with about 1,000 pages of dense mathematics and prose between them.

As a result there is a growing feeling, a cautious optimism that they have finally achieved a landmark not just of mathematics, but of human thought.

“It’s really a great moment in mathematics,” said Bruce Kleiner of Yale, who has spent the last three years helping to explicate Dr. Perelman’s work. “It could have happened 100 years from now, or never.”

In a speech at a conference in Beijing this summer, Shing-Tung Yau of Harvard said the understanding of three-dimensional space brought about by Poincaré’s conjecture could be one of the major pillars of math in the 21st century.

Quoting Poincaré himself, Dr.Yau said, “Thought is only a flash in the middle of a long night, but the flash that means everything.”

But at the moment of his putative triumph, Dr. Perelman is nowhere in sight. He is an odds-on favorite to win a Fields Medal, math’s version of the Nobel Prize, when the International Mathematics Union convenes in Madrid next Tuesday. But there is no indication whether he will show up.

Also left hanging...

(Excerpt) Read more at nytimes.com ...

first

Xianfeng David Gu and Shing-Tung Yau

Even topologists don’t think this soap film can be made into a sphere.

Xianfeng David Gu and Shing-Tung Yau

To a topologist, a rabbit is the same as a sphere. Neither has a hole. Longitude and latitude lines on the rabbit allow mathematicians to map it onto different forms while preserving information.

Graphic: The Essential Grisha P.S. Enlarge the graphic to read it.

To: **neverdem**

Nerd Nirvana.

2
posted on **08/14/2006 11:41:11 PM PDT**
by HisKingdomWillAbolishSinDeath
(Jesus always reads His knee-mail. (Hall of Fame Hit-N-Run poster))

To: **neverdem**

bookmark for later

3
posted on **08/14/2006 11:41:45 PM PDT**
by Bush_Democrat
(Ex-Dem since 2001 *Folding@Home for the Gipper - Join the FReeper Folders*)

To: **neverdem**

I'd be interested to know if this proof has any practical implications or uses.

To: **neverdem**

Cool story.

I am excited that a new world has opened up for mathematicians. That means new worlds open for the rest of us down the line.

Not that I understand a THING about it, mind you!

To: **neverdem**

Og bored!

To: **neverdem**

7
posted on **08/15/2006 12:04:52 AM PDT**
by msnimje
("Beware the F/A - 22 Raptor with open doors" -- Unknown US NAVY Raptor Pilot)

To: **neverdem**

Huh?

To: **RussP**

EVERYTHING matters...

To: **Vanders9**

But is matter truly everything?

10
posted on **08/15/2006 12:15:33 AM PDT**
by wyattearp
(Study! Study! Study! Or BONK, BONK, on the head!)

To: **Doctor Stochastic; Pikachu_Dad**

ping

To: **msnimje**

I'm still working on how they got all those tomatoes in that little bitty can.

12
posted on **08/15/2006 12:36:45 AM PDT**
by garyhope
(It's World War IV, right here, right now courtesy of Islam.)

To: **neverdem**

The Poincare conjecture states (roughly) that 3-dimensional balls are, give or take some stretching, the only 3-dimensional object that has no holes. This conjecture has been generalized from 3 dimensions to N dimensions, but for the higher dimensions, it was already proved. Grigori Perelman proved it for the case of N == 3, which was Poincare's original conjecture.

13
posted on **08/15/2006 12:38:33 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **neverdem**

This is from: http://www.answers.com/topic/poincar-conjecture **:**

At the beginning of the 20th century, Henri Poincaré was working on the foundations of topology — what would later be called combinatorial topology and then algebraic topology. He was particularly interested in what topological properties characterized a sphere.

Poincaré claimed in 1900 that homology, a tool he had devised and based on prior work of Enrico Betti, was sufficient to tell if a 3-manifold was a 3-sphere. In a 1904 paper he described a counterexample, now called the Poincaré sphere, that had the same homology as a 3-sphere. Poincaré was able to show the Poincaré sphere had a fundamental group of order 120. Since the 3-sphere has trivial fundamental group, he concluded this was a different space. This was the first example of a homology sphere, and since then, many more have been constructed.

In this same paper, he wondered if a 3-manifold with the same homology as a 3-sphere but also trivial fundamental group had to be a 3-sphere. Poincaré's new condition, i.e. "trivial fundamental group", can be phrased as "every loop can be shrunk to a point".

The original phrasing was as follows:

*Consider a compact 3-dimensional manifold V without boundary. Is it possible that the fundamental group V could be trivial, even though V is not homeomorphic to the 3-dimensional sphere?*

Poincaré never declared whether he believed this additional condition could distinguish the 3-sphere, but nonetheless, the statement that it does has come down in history as the Poincaré conjecture. Here is the standard form of the conjecture:

*Every simply connected closed (i.e. compact and without boundary) 3-manifold is homeomorphic to a 3-sphere. Loosely speaking, this means that if a given 3-manifold is "sufficiently like" a sphere (most importantly, that each loop in the manifold can be shrunk to a point), then it is really just a 3-sphere.*

They never say too much about what Perelman actually did.

At the beginning of the 20th century, Henri Poincaré was working on the foundations of topology — what would later be called combinatorial topology and then algebraic topology. He was particularly interested in what topological properties characterized a sphere.

Poincaré claimed in 1900 that homology, a tool he had devised and based on prior work of Enrico Betti, was sufficient to tell if a 3-manifold was a 3-sphere. In a 1904 paper he described a counterexample, now called the Poincaré sphere, that had the same homology as a 3-sphere. Poincaré was able to show the Poincaré sphere had a fundamental group of order 120. Since the 3-sphere has trivial fundamental group, he concluded this was a different space. This was the first example of a homology sphere, and since then, many more have been constructed.

In this same paper, he wondered if a 3-manifold with the same homology as a 3-sphere but also trivial fundamental group had to be a 3-sphere. Poincaré's new condition, i.e. "trivial fundamental group", can be phrased as "every loop can be shrunk to a point".

The original phrasing was as follows:

Poincaré never declared whether he believed this additional condition could distinguish the 3-sphere, but nonetheless, the statement that it does has come down in history as the Poincaré conjecture. Here is the standard form of the conjecture:

They never say too much about what Perelman actually did.

To: **neverdem**

Rabbits have five holes (or more)

To: **ThePythonicCow**

It takes a thousand pages of math to do that?

To: **RussP**

Dr. Morgan said the excitement came not from the final proof of the conjecture, which everybody felt was true, but the method, “finding deep connections between what were unrelated fields of mathematics.”

--snip--

In the early 1980’s Richard Hamilton of Columbia suggested a new technique, called the Ricci flow, borrowed from the kind of mathematics that underlies Einstein’s general theory of relativity and string theory, to investigate the shapes of spaces.

I don't think it should be discounted.

17
posted on **08/15/2006 12:46:39 AM PDT**
by neverdem
(May you be in heaven a half hour before the devil knows that you're dead.)

To: **ThePythonicCow**

Ah - from Clay Mathematics Institute comes this more accurate statement of this conjecture:

## Poincaré Conjecture

If we stretch a rubber band around the surface of an apple, then we can shrink it down to a point by moving it slowly, without tearing it and without allowing it to leave the surface. On the other hand, if we imagine that the same rubber band has somehow been stretched in the appropriate direction around a doughnut, then there is no way of shrinking it to a point without breaking either the rubber band or the doughnut. We say the surface of the apple is "simply connected," but that the surface of the doughnut is not. Poincaré, almost a hundred years ago, knew that a two dimensional sphere is essentially characterized by this property of simple connectivity, and asked the corresponding question for the three dimensional sphere (the set of points in four dimensional space at unit distance from the origin). This question turned out to be extraordinarily difficult, and mathematicians have been struggling with it ever since.

18
posted on **08/15/2006 12:52:43 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **StJacques**

What's a 3-Sphere?

To: **Vanders9**

Even antimatter?

What about Cotton Matthers?

20
posted on **08/15/2006 12:59:35 AM PDT**
by rawcatslyentist
(I'd rather be carrying a shotgun with Dick, than riding shotgun with a Kennedyl! *-0(:~{>)

To: **StJacques**

Thurston's Geometrization Conjecture

Thurston's conjecture proposed a complete characterization of geometric structures on three-dimensional manifolds.

Before stating Thurston's geometrization conjecture in detail, some background information is useful. Three-dimensional manifolds possess what is known as a standard two-level decomposition. First, there is the connected sum decomposition, which says that every compact three-manifold is the connected sum of a unique collection of prime three-manifolds.

The second decomposition is the Jaco-Shalen-Johannson torus decomposition, which states that irreducible orientable compact 3-manifolds have a canonical (up to isotopy) minimal collection of disjointly embedded incompressible tori such that each component of the 3-manifold removed by the tori is either "atoroidal" or "Seifert-fibered."

Thurston's conjecture is that, after you split a three-manifold into its connected sum and the Jaco-Shalen-Johannson torus decomposition, the remaining components each admit exactly one of the following geometries:

4. The geometry of ,

5. The geometry of ,

6. The geometry of the universal cover of the Lie group ,

7. Nil geometry, or

8. Sol geometry.

Here, is the 2-sphere (in a topologist's sense) and is the hyperbolic plane. If Thurston's conjecture is true, the truth of the Poincaré conjecture immediately follows. Thurston shared the 1982 Fields Medal for work done in proving that the conjecture held in a subset of these cases.

Six of these geometries are now well understood, and there has been a great deal of progress with hyperbolic geometry (the geometry of constant negative scalar curvature). However, the geometry of constant positive curvature is still poorly understood, and in this geometry, the Thurston elliptization conjecture extends the Poincaré conjecture (Milnor).

Results due to Perelman (2002, 2003) appear to establish the geometrization conjecture, and thus also the Poincaré conjecture. Unlike a number of previous manuscripts attempting to prove the Poincaré conjecture, mathematicians familiar with Perelman's work describe it as well thought-out and expect that it will be difficult to locate any mistakes (Robinson 2003).

21
posted on **08/15/2006 1:04:22 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **Greystoke**

A 3-sphere is a solid ball - or warped equivalent. In 4-dimensional space, the set of points one unit from the origin is one example of a 3-sphere, just as in our ordinary 3-dimensional space, the set of points one unit from some point is an example of a 2-sphere that is more commonly called a circle.

22
posted on **08/15/2006 1:08:26 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **wyattearp**

I have detected a flaw in Dr. Perelman's work. You have 100 years to prove me wrong.

yitbos

23
posted on **08/15/2006 1:10:08 AM PDT**
by bruinbirdman
("Those who control language control minds. " - Ayn Rand)

To: **HiTech RedNeck**

Rabbits (and humans) don't have five holes. If you model the alimentary canal, from mouth to anus, they have one hole. Indentations don't count as holes. If you model the sinus cavities and nasal passages, and their connection to the alimentary canal, then they get holier - I guess you might be able to get to five holes that way. I'm no otorhinolaryngologist, so couldn't say for sure.

24
posted on **08/15/2006 1:12:00 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **neverdem; All**

To: **wyattearp**

ooh...philosophy!

If we are to believe Einstein, then energy and matter are interchangeable. This however, does not account for the transphysical and supernatural, so I would concur with the opinion that matter is not everything.

The point is moot however, as my use of the term "matters" is in its alternate meaning of "having significance", rather than that of "corporeal existance". I suspect that you were aware of that point prior to your reply, but chose to ignore it for jocular reasons.

:)

To: **HiTech RedNeck**

Do they?

Cats only have two holes in their skin. I cant believe rabbits are more endowed.

To: **rawcatslyentist**

...now you're being silly...

To: **ThePythonicCow**

Don't forget the tear ducts. And if you want to get really technical, the porous skin.

To: **ThePythonicCow**

Give that man $1,000,000; if you can find him.

yitbos

30
posted on **08/15/2006 1:28:25 AM PDT**
by bruinbirdman
("Those who control language control minds. " - Ayn Rand)

To: **Vanders9**

Its their EYES!!

ooh...what you were all thinking!

To: **Vanders9**

I'm havin a BALL !!!

32
posted on **08/15/2006 1:30:55 AM PDT**
by rawcatslyentist
(I'd rather be carrying a shotgun with Dick, than riding shotgun with a Kennedyl! *-0(:~{>)

To: **ThePythonicCow**

"Rabbits (and humans) don't have five holes. If you model the alimentary canal, from mouth to anus, they have one hole. Indentations don't count as holes. If you model the sinus cavities and nasal passages, and their connection to the alimentary canal, then they get holier - I guess you might be able to get to five holes that way. I'm no otorhinolaryngologist, so couldn't say for sure. "

- - - - - - - - - - - - -

That's true, there are only four holes (mouth, anus, and the Eustachian tubes (containing our hearing apparatus to the hole connecting the mouth and anus). The "hole" in mammals from which urine emits, and which serves the reproductive function does not connect to these other passageways,and does not exit at some other point so it is only an indentation, not a true hole. Thus the topology of the mammalian body surface (ignoring, as you say, the possibility of multiple true holes in the sinus cavity) is topologically equivalent to a donut with four holes.

Is there an anatomy specialist in the house who can comment on the topological character of the sinuses, and the lungs which could also have large numbers of true holes (in the topological sense)?

To: **Blue_Ridge_Mtn_Geek**

34
posted on **08/15/2006 1:41:42 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **ThePythonicCow**

Ah - from Clay Mathematics Institute comes this more accurate statement of this conjecture:

Poincaré Conjecture

= = = = = = = = = = = = = = = = = = = = = = = = = =

Yes, one of the implications for the author, if this proof holds up and is published in a vetted math journal, is a Clay prize of $1 million. The Poincare Conjecture is one of their "Millenium Problems". For the other six, with formal statements of all seven, see the Clay Institute site (Google it!).

To: **Blue_Ridge_Mtn_Geek**

36
posted on **08/15/2006 1:42:39 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **neverdem**

"I wish I'd read that book by that wheelchair guy!"

37
posted on **08/15/2006 1:43:16 AM PDT**
by WestVirginiaRebel
(Common sense will do to liberalism what the atomic bomb did to Nagasaki-Rush Limbaugh)

To: **ThePythonicCow**

the Eustachian tubes

I don't think the Eustachian tubes go all the way through, unless you have a burst ear drum. So they are long skinny indentations, not holes.

= = = = = = = = = = = = = = = = = = = = = = = = = =

Perhaps so. I thought the ear drums were suspended on bones, but didn't necessarily cover the entire passage (but I'm no expert on this, just recalling some high school anatomy studies from 40+ years ago). Is there another here familiar with mammalian anatomy who can help us out?

To: **Blue_Ridge_Mtn_Geek**

The ear drum covers the entire passage -- that's why your ears pop when your airline flight comes in for a landing. The air in the outer ear cannot quickly equalize pressure with that in the middle ear. The ear drum separates the outer and middle ear canals.

39
posted on **08/15/2006 1:48:52 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

To: **HiTech RedNeck**

"It takes a thousand pages of math to do that?"

= = = = = = = = = = = = = = = = = = = = = = = = ==

That's one of the fascinating things about some of the "really hard" math questions - - -fairly easy to state, in a way that non-specialists can understand, but brutally difficult to answer rigorously, requiring the development of whole new mathematical apparatuses and methods to solve.

Two recent (late 20th century) examples are the solutions of "Fermat's Last Theorem" and the "Four Color Problem" (Google for details).

Invariably the spinoff results from these new techniques and insights are far more fruitful than simply the resolution of the question that is the object of the investigtion. That's why military establishments and modern technological enterprises commit a certain part of their budgets to funding "pure math research". See

http://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.html

http://www.dartmouth.edu/~matc/MathDrama/reading/Hamming.html

for two papers, one by a physicist and the other by an applied mathematician, both called "The Unreasonable Effectiveness of Mathematics in the Natural Sciences" for further discussion of this point.

To: **ThePythonicCow**

mouth, anus

And the mouth and anus are not two holes, but two ends of one hole, the alimentary canal.

= = = = = = = = = = = = = = = = = = = = = = = = = = = = =

True, and so if you are correct about the Eustachian tubes (and ignoring the lungs and sinus cavity which may or may not add to the count), there is indeed only "one hole" in the topological sense. And, if I am correct about those 'holes in our ears' there are, how many? Still four in that case, I think. "But I could be wrong".

To: **bruinbirdman**

Look over there--you forgot to carry the 1.

To: **ThePythonicCow**

"The ear drum covers the entire passage -- that's why your ears pop when your airline flight comes in for a landing. The air in the outer ear cannot quickly equalize pressure with that in the middle ear. The ear drum separates the outer and middle ear canals."

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Is the fit "tight" but not "secure", sometimes temporarily obstructed by excretions? Else, are our ear drums broken whenever we experience a "pop" like that, or is a wider opening through which the pressure is equalized being created through the fluid and mucous which also sometimes occupies that passage? I notice that my ears have to "pop" when my sinuses are congested, but they don't when I'm breathing freely.

To: **neverdem**

This is all fascinating. All Mathematics can be explained through nature in relation to pi. Duh...

44
posted on **08/15/2006 2:08:41 AM PDT**
by lmr
(You can have my Tactical Nuclear Weapons when you pry them from my cold dead fingers.)

To: **wyattearp**

That is not a mathematical question. Perhaps, an E=Mc squared figures into that, but it is a question of science. Is matter particles of light? Or better yet, are particles of light matter? Einstein theorized one in the same...

45
posted on **08/15/2006 2:12:28 AM PDT**
by lmr
(You can have my Tactical Nuclear Weapons when you pry them from my cold dead fingers.)

To: **neverdem**

I like pictorials.

Have you ever seen a one sided figure?

46
posted on **08/15/2006 2:13:53 AM PDT**
by stands2reason
(ANAGRAM for the day: Socialist twaddle == Tact is disallowed)

To: **neverdem**

It should be noted that this proof may yet have a hole [no pun intended!], and if so it may take some time to discover it. There are precedents, e.g., Wiles agonizing extra year of work to plug the hole found after his initial announcement of a solution of the "Fermat Theorem" (for which he won a Clay Prize since that is one of the Millenium Seven):

http://en.wikipedia.org/wiki/Fermat's_last_theorem

(sorry, the syntax is correct, but the link generator must have a bug - - cut and paste the entire URL into your browser if you want to check out the reference)

"The story of the proof is almost as remarkable as the mystery of the theorem itself. Wiles spent seven years working out nearly all the details by himself and with utter secrecy (except for a final review stage for which he enlisted the help of his Princeton colleague, Nick Katz). When he announced his proof over the course of three lectures delivered at Isaac Newton Institute for Mathematical Sciences on June 21-23 1993, he amazed his audience with the number of ideas and constructions used in his proof. Unfortunately, upon closer inspection a serious error was discovered: it seemed to lead to the breakdown of this original proof. Wiles and Taylor then spent about a year trying to revive the proof. In September 1994, they were able to resurrect the proof with some different, discarded techniques that Wiles had used in his earlier attempts."

To: **Blue_Ridge_Mtn_Geek**

Sorry, I'm wrong about the Fermat Theorem being one of the Millenium Seven - - - it was solved in 1994, before Clay Institute even announced the "Millenium Problems". I need to get some sleep! Good morning.

To: **neverdem**

Sorry, one more reference I can't resist sharing, then to bed:

http://math.stanford.edu/~lekheng/flt/

Bluff your way in Fermat's Last Theorem

To: **Blue_Ridge_Mtn_Geek**

When our ears "pop", the air flow is threw the Eustachian tube, between the middle ear and the back of the throat. Nothing flows past the ear drum. When your sinuses are clear, the Eustachian tubes let the air flow more freely.

50
posted on **08/15/2006 2:39:18 AM PDT**
by ThePythonicCow
(We are but Seekers of Truth, not the Source.)

first

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