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by Vayutuvan
30 Nov 2011 04:51
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Kiran Kedlaya on Jeopardy

Some of you - esp. AmberG - might get a kick out of this.

Kiran Kedlaya was a contestant on Jeopardy today and won. So he will be on tomorrow as well.
by Vayutuvan
25 Nov 2011 07:16
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Physics based on Discrete Structures

I came across the following quote in one of the discussion lists I subscribe to. Thought this might be of interest to Bade saar and Kasturi garu and others. "I consider it quite possible that physics cannot be based on the field concept, i. e., on continuous structures. In that case _nothing_ r...
by Vayutuvan
23 Nov 2011 02:08
Forum: History & Current Affairs Archive
Topic: Discussion on Indian Epics, Texts, Treatises & Kathas
Replies: 4574
Views: 560176

Re: Discussion on Indian Epics, Texts, Treatises & Kathas

what "bitter end"? when Duryodhana himself is dying, the idiot goes out to destroy the "poudha" of the Pandavas. when he goes out to kill the baby in the womb, Kauravas already lost for all intents and puposes, and yet he tries to create more destruction by trying to completely ...
by Vayutuvan
23 Nov 2011 01:19
Forum: History & Current Affairs Archive
Topic: Discussion on Indian Epics, Texts, Treatises & Kathas
Replies: 4574
Views: 560176

Re: Discussion on Indian Epics, Texts, Treatises & Kathas

I will hunt for the verses from MBH and paste them here shortly (by end of next week). about Ashwatthama, well he is the "Paki" character. Atri Ji Is he really? During the Sri Krishna Rayabara he sides with Krishna (and thus Pandava side), but he has to remain loyal to his master and patr...
by Vayutuvan
27 Oct 2011 00:56
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

I'd like to raise my knowledge of applied math in general. i.e. learn techniques of problem solving primarily for engineering problems. I know the field of math is vast but what book can you recommend that starts at a basic level (and i emphasize basic) yet leaves me with a reasonably good knowledg...
by Vayutuvan
19 Sep 2011 22:59
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

Duck fox problem answer in the form of a puzzle :) - Assuming no fish in the pond, either both die of hunger or both die of Fatigue ^^^Can you expand on that? One can safely assume that by "escape" here, one means: the duck in a finite time escapes by flying away. (one can even put reason...
by Vayutuvan
19 Sep 2011 21:32
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

Duck fox problem answer in the form of a puzzle :) -
Assuming no fish in the pond, either both die of
hunger or both die of Fatigue
by Vayutuvan
05 Sep 2011 23:27
Forum: Strategy, Politics & International Relations Forum
Topic: The Jan Lokpal Bill, Anna Hazare, and Baba Ramdev II
Replies: 3078
Views: 385553

Re: The Jan Lokpal Bill, Anna Hazare, and Baba Ramdev II

nukavarapu wrote:...
-- Yellow people who wants to take pieces out of the country
That is a little beyond the pale
by Vayutuvan
16 Aug 2011 01:06
Forum: Trash Can Archive
Topic: Happy Independence Day!
Replies: 48
Views: 9052

Happy Independence Day!

A very happy I-day to all. Hope all you in India enjoyed the prabhat bheri and jhenda vandanam.
by Vayutuvan
05 Aug 2011 05:35
Forum: Trash Can Archive
Topic: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2011
Replies: 2855
Views: 489210

Re: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2

Is it true that they are really discontent? The bakis I interact with are all ga-ga over bakistan, ... If they are sooo discontent then why they do not do what their ummah brothers are doing in syria or egypt? disha ji There is difference between Syria and Paistan - Syria has far higher literacy le...
by Vayutuvan
05 Aug 2011 05:05
Forum: Trash Can Archive
Topic: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2011
Replies: 2855
Views: 489210

Re: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2

1. We also had had a small part in putting ourselves in "Soviet Camp". What was our part? SwamyG ji This is all OT in this thread (and moreover it is ancient history, so last post) Our voting pattern in the UN was either vote against US or abstain when it would have helped US. Of course, ...
by Vayutuvan
05 Aug 2011 03:30
Forum: Trash Can Archive
Topic: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2011
Replies: 2855
Views: 489210

Re: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2

Was #1 by choice? How do you actively work towards break up of bakistan? Help the bad taliban to become the good taliban or help the good taliban to become the bad taliban? You are right. While it was involuntary to a large extent, may be we could have done something. I don't know what. "activ...
by Vayutuvan
05 Aug 2011 02:12
Forum: Trash Can Archive
Topic: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2011
Replies: 2855
Views: 489210

Re: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2

...1. What Pakistan did was to bend over backwards to accommodate the cold war concerns of the US, helping to place India in the "soviet camp". Pakistan also played on China's fears of India to ingratiate themselves with China. ... ... India is faced with two choices 1. Don't make war wit...
by Vayutuvan
30 Jul 2011 03:24
Forum: Trash Can Archive
Topic: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2011
Replies: 2855
Views: 489210

Re: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2

JE Menon wrote:Meanwhile, note that the author of the article is a cousin of HR Khar :rotfl: ... minor league back-scratching going on :roll:
asinus asinum fricat - A jackass rubs another jackass
by Vayutuvan
27 Jul 2011 06:29
Forum: Trash Can Archive
Topic: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2011
Replies: 2855
Views: 489210

Re: Terrorist Islamic Republic of Pakistan (TSP): June 30, 2

Nandu wrote:...Paki side have always been in the vein of "let us try to win at the negotiating table what we couldn't in the battlefield", ...
IIRC, this was said by the Russians during the Tashkent talks when LBS was the PM.
by Vayutuvan
10 Jul 2011 22:19
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

^^^ tan(a + b) = (tan(a) + tan(b)) / (1 - tan(a) * tan(b)) This looks a heck of a lot like your formula, where x[n] = tan(a) and x[n+1] = tan(b) and x[n+2] = tan(a + b). Now the rest of it is pretty easy to figure out :) Nice computer assited pattern recognition. This is how computers can help - si...
by Vayutuvan
10 Jul 2011 04:48
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

^
OK. Tried some simple iterations to see if telescoping kind of trick can be applied. Hmm... could it be zero?
by Vayutuvan
09 Jul 2011 23:58
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

In my opinion, It does not matter much what you use, "side" or "edge", both are vague, unless you define what you mean by "volume", "box" etc.. in k-dimension..Also meaning of "different" (as in - is 1 x 3 box different than 3 x 1 box..In three dim ...
by Vayutuvan
08 Jul 2011 19:50
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: A puzzle - simple if you remember a theorem

Given a number n and k, how many different k-dimensional boxes of volume n with integral sides can be got? Assume that the sides of the boxes are parallel to the coordinate axes. Hello, Can you define the problem clearly please. What is a k-dimensional box ? What is meant by integral side ? What is...
by Vayutuvan
08 Jul 2011 03:42
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

A puzzle - simple if you remember a theorem

As promised, here is a problem whose solution can be represented as a computer program (i.e. algorithm) very easily.

Given a number n and k, how many different k-dimensional boxes of volume n with integral sides can be got? Assume that the sides of the boxes are parallel to the coordinate axes.
by Vayutuvan
08 Jul 2011 02:18
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

brihaspati wrote:Well how about thinking of a small "square" on the "surface"
Bji

Nice
by Vayutuvan
08 Jul 2011 01:49
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

Younger days would have read up all the books and tried to understand it. Unfortunately miles to go before I sleep. Cool, My intention was not to be dense but since it comes up quite often just wanted to define it completely and unambiguously. The problem is that once one goes to more than one vari...
by Vayutuvan
08 Jul 2011 00:19
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

Thanks for the explanation. So Jacobin for first derivative and then Hessian for second derivative? When the function is scalar valued, then the Jacobian is called the gradient and is a vector, but yes, Jacobian is a generalization of the first derivative to vector-valued functions of several varia...
by Vayutuvan
07 Jul 2011 22:13
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

AmberG, What is this Hessian operator? Where is it used and what are its advantages? Ramana garu If I may, it is the second derivative analogue for a scalar valued function of several variables and is a matrix whose entries are defined to be Let $H$ be the Hessian matrix for a function $f(x_1,x_2,....
by Vayutuvan
01 Jul 2011 00:15
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Talking of pop physics books...

I really liked Interactions by Sheldon Glashow (Nobel Laureate along with Salam and Weinberg). Planning to re-read. What do the Physics gurus here think?
by Vayutuvan
29 Jun 2011 01:11
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

Unless someone comes up proving P=NP, in which case we can hope to have non-deterministic polynomial algorithms have polynomial solutions. That would be one of the greatest break through (almost equivalent to solving Riemann hypothesis), but yet COD will still be an issue. Even the simplest n-body ...
by Vayutuvan
28 Jun 2011 03:25
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

No use blaming the dimensions. That problem arises because physicists are driven to explain as much by as little as possible. The incorporation of higher number of dimensions is simply to bring together the current three-interaction (some will say two) model into a single GUT. They want one single ...
by Vayutuvan
26 Jun 2011 22:15
Forum: Science, Economics & Technology Forum
Topic: Physics Discussion Thread
Replies: 2921
Views: 7360398

Re: Physics Thread.

The potential is exactly 1/r, not 1/r^1.1 or 1/r^0.9 -- why? Similarly, the electrostatic potential is also 1/r. Is that a coincidence? To me, there is something deep which science has not yet fully grasped. Guru Prabhu ji Interesting question I had been ruminating on for sometime. On what basis ar...
by Vayutuvan
26 Jun 2011 21:57
Forum: Trash Can Archive
Topic: India-US Strategic News and Discussion
Replies: 3942
Views: 708810

Re: India-US Strategic News and Discussion

Would they have dared to do this to any islamic country?? Another way of looking at it is that it is a vote of confidence of the Indian pluralism. Wasn't a law passed in India decriminalizing LGBT recently? This is could be a recognition of that fact. If he is good for India, what matter his esxual...
by Vayutuvan
26 Jun 2011 06:01
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: Brahmagupta's method

Any way, as you know this is known as Erdos-Moser conjuncture.. http://mathworld.wolfram.com/Erdos-MoserEquation.html The limit for lower value of n has been raised to about 10^1000000000 now.(see below) ... BTW there is a talk in December in Amsterdam which you may find interesting... http://event...
by Vayutuvan
21 Jun 2011 22:39
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: Brahmagupta's method

Few comments.. Can you post the "interesting theorem from Leo Moser's book? P.S... In number theory, sigma (small sigma) is generally used to represent sum of all the factors of a number. Eg (sigma(6)=1+2+3+6=12) , in that case for any prime number (and prime numbers only) sigma(n)=n+1. Inform...
by Vayutuvan
21 Jun 2011 00:50
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Brahmagupta's method

an observation - brahmagpta's series, if i may coin the term, is similar to fibonocci's series. defining both recursively, we get fibonocci: $f_1 = 1; f_2 = 1; f_i = f_{i-1} + f_{i-2}$ brahmagupta: $f_1 = 1; f_2 = 2; f_i = 2 f_{i-1} + f_{i-2}$ both are second order linear recurrence relation with co...
by Vayutuvan
20 Jun 2011 20:03
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

Folks - Diophantine equations (see wiki, if not familiar with the term)could be interesting and could be very hard. Amber ji and others Hilbert's 10th problem which asks for an "algorithm" (he did not use that particular word as that concept came much later due to Turing, Church and Emile...
by Vayutuvan
20 Jun 2011 05:19
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

Are you sure? How about (1+2+...49) which is 1225 = 35^2... (or looking at it as 49*(50/2) = 49*25) Or even (1+2+3....1681) which is 1189^2 :) I only got as far as follows: Suppose $\Sigma_{i=1}^{n} i = m^2$ The following condition has to be satisfied (m^2 mod 4 = 1) && (n mod 4 = 1 || n+1 ...
by Vayutuvan
20 Jun 2011 04:55
Forum: Science, Economics & Technology Forum
Topic: BR Maths Corner-1
Replies: 2239
Views: 472821

Re: BR Maths Corner-1

SaiK wrote:Amber ji, any good text books on discrete math that you recommend.
If I may, Elements of Discrete Mathematics by C.L. Liu (ISBN 0-07--038133-X) is an introductory classic.