Serialized books: a neat idea…

From BoingBoing, this link comes our way:

Matt Webb says:

I want to read the Notebooks, but there are 1,565 pages and I have too much else to read.

At a page a day it would take a little over four years, but be manageable.

Fortunately Project Gutenberg (who make freely available online out-of-copyright books) has created a text version of the Notebooks of Leonardo Da Vinci. You can download it. It lacks the illustrations of the original, but it’s Good Enough.

Using this site, I can read one page a day using my RSS News Reader. Find an RSS News Reader. I started at page 1 on May 30th, 2004. I’m now on page 2. You can either read along with me, or start reading at page 1 today.

Get the RSS feeds here.

Published in: on May 31, 2004 at 2:12 pm Leave a Comment

Coffee

Unattributed quote:

A mathematician is a machine for turning coffee into theorems



Paul Erdos, after going off coffee for a month:

You have set back the cause of mathematics for a month

And finally, Ziggy (and this will now be my unofficial logo):

Published in: on May 28, 2004 at 6:12 pm Comments (4)

A Nice Box Theorem

I was at Peter Winkler’s last talk at Bell Labs before he leaves for Dartmouth.

TOURNAMENTS, BOXES AND NON-TRANSITIVE DICE

Many gymnasts compete in 2k-1 events, and are ranked in each with no ties. One competitor is deemed to have “beaten” another if she outscores the other in a majority of the events.

Afterward the organizers are embarrassed to discover that no matter how they award the prizes, there will always be a gymnast who didn’t get a prize but beat every gymnast who did.

How many prizes should the organizers have had on hand to be sure this wouldn’t happen?

(A meandering blackboard presentation based on recent work with N.Alon, G.Brightwell, H.Kierstead, and A.Kostochka.)



During this lecture he presented this gem, due to Imre Bárány and Jenö Lehel:



There exists a constant c = c(d) such that for any compact set S contained in Rd, there exists a subset A of S of size at most c such that S is contained in the union of “boxes” of pairs of points of A, where the box containing two points p and q is defined the smallest orthogonal box containing p and q.



A lower bound on c is doubly exponential in d (for d = 2, 4 points suffice).


Peter Winkler’s talks are always beautiful this way; they start with a simple puzzle – something you could describe in a line or so – and then as the talk progresses, you realize the deeper and deeper levels of mathematics that are being used to solve the problem.

Published in: on at 5:24 pm Leave a Comment

Rappamatics !

Courtesy of Aaron ‘A-Dogg’ Archer, some excerpts of PHAT Rappamatics….

U Can’t Bound This



Cutting planes, by far

best found in a dimly lit bar

so flip, that coaster in the air {ADogg flips a coaster}

Call Bill Cook, run a comb through your hair

Now follow, the central path

Scale that data make your polytope phat

So make, your step-size large

Do this in practice, it’s fast to converge.

[quadratic convergence]

Ramanujan’s Revenge

….

I need a math transfusion.

My blood pressure’s turnin’ into fusion.

I’ve been racin’ and pacin’ ,

sweepin’ the nation

‘cuz mathematic lingo is what we’re facin’ .

Talkin’ homomorphic, endomorphic, isomorphic, automorphic,

homotopic, isotopic, polytopic, can t stop it.

Every single theorem that I hold in my pocket

is BAD, too hot to handle.

I’ve got theorems that would cause a scandal.

Activated, iterated, integrated, combinated,

numerated, permutated, bifurcated, conjugated.

I can’t stop, ‘cuz the rhythm has got me.

Without math you re Mr. Softee,

and if you disagree that math is happenin’ ,

I’ll be on your butt like a contraction mappin’ .

Down with MIP?

Yeah, you know me.

Down with MIP?

Yeah, you know me.

Down with MIP?

Yeah, you know me.

Who’s down with MIP?

All the homies.

Word.

Published in: on May 27, 2004 at 5:40 am Comments (2)

Zipf’s Law and Log-Normal Distributions.

If you have ever done data analysis, you have probably bumped into the (in)famous Zipfian distributions, popularized by the “80-20″ law:

80% of the work is done by 20% of the people

or

The probability of the ith most frequent item is roughly i-alpha

Michael Mitzenmacher has a nice survey (PS) outlining the history of such “power-law” distributions, the generative processes that create such distributions and their relationship to log-normal distributions (a distribution where the log of the variable is normally distributed). Worth a read…

Published in: on at 12:01 am Leave a Comment

Mathematicians don’t understand math !!!

STOP THE PRESSES !

I feel the urge to fisk violently upon reading an article in today’s NYT titled ‘When Even Mathematicians Don’t Understand the Math’:

<.. deep breaths …>

Here are some choice excerpts:



Asked if there exist mathematical concepts that defy explanation to a popular audience, Dr. Stewart, author of “Flatterland: Like Flatland, Only More So” replied: “Oh, yes – possibly most of them. I have never even dared to try to explain noncommutative geometry or the cohomology of sheaves, even though both are at least as important as, say, chaos theory or fractals.”



I see. so this is news to the NYT that there are (perish the thought)mathematical ideas that cannot be explained to layman…

The Hodge conjecture deals not only with cohomology classes, a complicated group construct, but involves algebraic varieties, which Dr. Devlin describes as generalizations of geometric figures that really do not have any shape at all. “Those equations represent things that not only can we not visualize, we can’t even imagine being able to visualize them,” he said. “They are beyond visualization.” This difficulty points to a math truism that ultimately framed his entire project.

“What the book was really saying was, ‘You’re not going to understand what this problem is about as a layperson, but neither will the experts,’ ” he said, adding, “The story is that mathematics has reached a stage of such abstraction that many of its frontier problems cannot be understood even by the experts.”



Well sure – an expert in sub area X may not always understand the terms in sub-area Y. Is this (a) surprising or (b) a BAD BAD thing ? Isn’t this just the consequence of living in a rich and incredibly complex field ?



At the same time, higher math is used to decipher the existence and composition of the world. But how can it make sense that a nearly unintelligible language can explain the physical world?



There seems to be the unstated implication that a language unintelligible to the layman cannot be used to explain the world.. see below…



But if science writers described breakthroughs in genetics or zoology in terms of overarching aims and not concrete facts, readers would question the foundations of that field. That lay readers and scientists alike accept that they will never wrap their heads around much of higher math is evidence that it is a world unto itself.



But surely one can say the same thing about some of the denser theories of post-modern literary criticism, that it is incredibly hard for the layman, or even many literary theorists, to understand them. Is there some kind of subtle anti-intellectualism at work here – knowledge that is not accessible to the masses is not real knowledge ?

In fact, it is difficult to explain what math is, let alone what it says.

Sigh…two pages into the article, the writer figures it out…

“It isn’t science,” said Dr. John L. Casti, the author of “Five Golden Rules: Great Theories of 20th-Century Mathematics and Why They Matter.” “Mathematics is an intellectual activity – at a linguistic level, you might say – whose output is very useful in the natural sciences. I think the criteria that mathematicians use for what constitutes good versus bad mathematics is much more close to that of a poet or a sculptor or a musician than it is to a chemist.”

And just as one cannot define what it is that makes a moving phrase played on a violin moving, the essence of the superb equation may also be ineffable.

Finally something I can live with ;)

Published in: on May 25, 2004 at 10:04 pm Leave a Comment

Robot Origami

Computational geometers do origami.

Computational geometers do robotics.

And now, robots do origami:



“Our primary interest in origami is manipulation,” Balkcom writes on his web page. “We are currently working on understanding more complicated origami skills – like reverse folding, squash folding, the rabbit ear, and prayer folding – that require the simultaneous manipulation of multiple non-colinear creases.”

Published in: on at 7:03 pm Leave a Comment

Summertime…

…is here, and that means summer students. When I was a grad student, getting a summer job always entailed negotiating that dreaded question ‘Will you do programming’, which to me was always a warning sign that the project would involve only programming.

Now that I am on the other side of the fence, I still dislike having students come over to do programming work; however, the reality is that one has to find projects that are interesting, have some kind of business motivation, and yet have a three month timeline. It is well nigh impossible to guarantee results in a theoretical project in any fixed time (or at least I have not learnt the art of this yet :) ), so invariably summer projects tend to involve some kind of tool/system building so that one can demonstrate concrete progress in a short timespan.

The trick is to figure out a topic that is amenable to ‘covert theory’ that can lead to more satisfying long-term research. After all…



Before each summer is done

Their theorem will be unfurled

By the dawning of fall term

They’ll take over the world… with algorithms !!

(with apologies to Pinky and the Brain)

Published in: on at 4:09 am Leave a Comment

Graph Drawing

The Graph Drawing deadline is fast approaching (May 31). It might seem strange to have an entire conference devoted to drawing graphs. However, this is a very valuable area; one would be surprised to see the number of situations in which one needs to visualize a large graph, and needs a good algorithm to do so.

There are many different approaches to drawing graphs; edges as straight lines or splines, or orthogonal chains, vertices as boxes or circles or points, faces as rectangles or orthogonal polygons. An interesting graph drawing result on planar graphs is Fary’s theorem:



Any planar graph can be drawn with straight lines for edges and no crossings.



What makes the above result quite interesting is the following. Let a pseudoline arrangement be a collection of curves (each separating the plane into two parts) in which each pair intersects exactly once. Such a collection defines an arrangement of the plane (with faces, vertices and edges). Such an arrangement is stretchable if it is isomorphic to a straight line arrangement.

Not all pseudoline arrangements are stretchable. In fact, determining whether a given pseudoline arrangement is stretchable is NP-hard (due to Peter Shor).

Published in: on at 4:06 am Leave a Comment

Back from a trip…

Just back from vacation…while I get back up to speed, take a look at this

Published in: on May 21, 2004 at 6:44 pm Leave a Comment