Game Theory

I have been reading a bit on game theory and I find the subject fascinating. Thought I could share some interesting ideas.
A game is essentially the following - there are a set of agents and each of them follows a particular strategy. A game could be zero sum - i.e. only one of them win or it could be co-operative where the agents need to co-operate to get something done. I think game theory quantifies one of the biggest dilemnas of mankind - for self or common good? Meaning, if you are to do something, do you do it to maximize personal benefit or maximize joint benefit. Consider the famous Prisoner's Dilemna - there are 2 prisonors in different rooms. They have the choice of ratting or keeping quiet. If, both don't rat, both go free. If one rats, the other goes to jail for 10 years. However, if both rat on each other, then each goes to jail for 5 years. So, what is best for each prisoner to do?
If he assumes that the other prisinor is purely concerned only about himself, and is going to rat to maximize his personal benefit, it is in his best interest to rat as well. If he didn't he would go to jail for 10 years as opposed to 5. But, not ratting works if he has a strong reason to believe that the other person is not going to rat. If both people share this belief, both go free.
This brings up the famous Nash Equillibria. A system is supposed to be in Nash Equillibria if each party is following the best strategy for itself given the strategy that others are following. Everyone is doing the best for himself under the set of conditions. So, no one has reason to change strategy. Hence, it's in equillibrium. If, a set of people are nice to each other, then it's best to be nice, assuming that others are going to be nice. This can go on forever. It's stable.
But, what if suddenly someone is not nice. Even though it's not to his best interest, assume he is like that. What happens? A evolutionary stable strategy is one in which members are not affected by a new entrant with a different strategy. Meaning, a player who suddenly changes his strategy cannot harm others. A strategy which assumes no trust. It is robust. This is not necessarily the best for everyone. But, it's safe for everyone. It avoids losses, but it also minimizes gains. All strategies that animals follow are evolutionarily stable.
So, being good as a strategy works if everyone else is being good. Everyone does well. It's a Nash Equillibria. But, it's not evolutionarily stable. Even, if one of the players decide to cheat, all players need to take a more defensive strategy to prevent losses. What this means is that interest in the common good works as long as its shared across players. Even if one takes up a selfish strategy it forces others to take up a similar strategy.
A great example of this phenomena is the building up of global arsenals. It's a huge waste to do so, but it's the safest strategy. You don't gain anything, but you make sure that you lose nothing. It's evolutionarily stable, as it doesn't matter if another country likes you or not. But, if you assume that all countries like you, and all countries do that then it makes more sense to not have any arsenal. The basis for all this waste is a simple lack of trust.
The India-Pakistan conflict (or any conflict for that matter!) is another excellent example. Each side takes up more and more paranoid strategies, which make sure it doesn't lose, but it makes it more and more difficult to resolve as none can let down on it's strategy - it leads to immediate loss!
This kind of logic also extends to personal relationships, signing a pre-nuptial agreement is against the spirit of blindly trusting your partner. This probably reduces the happiness that you get out of your married life, but it makes it a lot safer for you if things go awry. Trust. Short on letters and long on benefits :D! That was quite a philosophical end to a very practical subject.
PS: More here. It's in any kind of system which has competition. Politics. Auctions. Markets. Biological systems.

Why god did not get tenure

1. He had only one major publication.
2. It was in Hebrew.
3. It had no references.
4. It wasn't published in a referenced journal.
5. Some even doubt he wrote it by himself.
6. It may be true that he created the world, but what has he done since than?
7. His cooperative efforts have been quite limited.
8. The scientific community has had a hard time replicating his results.
9. He never applied to the ethics board for permission to use human subjects.
10. When one experiment went awry he tried to cover it by drowning his subjects.
11. When subjects did not behave as predicted, he deleted them from the sample.
12. He rarely came to class, just told the students to read the book.
13. Some say he had his son teach the class.
14. He expelled his first two students for learning.
15. Although there were only 10 requirements, most of his students failed his tests.
16. His office hours were infrequent and usually held on a mountaintop.
More here.

Pulitzer 1993

This photo of a girl crawling to a food shelter during the Sudan famine was taken by Kevin Carter, a South African photographer. He won the Pulitzer Prize in 1993 for this photo. He was deeply depressed by the experience and committed suicide in 1994. Here is the story.

Parfum

Old readers of my blog will know about my escapades in France. It was a time I had not much money (not that I have much now, but then I had not much of my dad's money, now I have not much of my own, it makes a difference) and France being France and with me in it I had to try:
1) Le Vin - The wine. So, I used to go to this grocery store opposite my dorm and buy a different variety every couple of days. Ok, every weekend. I am not a alchoholic. 6 euros for some very decent wine. So, not a very expensive pursuit to have. Yeah, there is stuff for 200 euros, but I wouldn't be allowed to enter those stores. I would atleast invite some very condescending looks. So peace. Maybe, I should review this sometime. Sometime. Beer and Wine review. I am guessing it would be very popular.
2) La Parfum - This is an expensive habit. One bottle of those chemicals sears a 50$ hole in your wallet. So, I thought, 'Hmm..Me in France..France=Parfum..So..why not some Parfum'. So, whenever I went to the mall, I used to drop by this store called Sephora (excellent store, amazing range, about 60m of wall space, just perfume, the US sucks) and try out the colognes. The aim was, try out all the colognes and eventually purchase. The best. Le meilleur. Which one did I buy:
Givency pour Homme by Givenchy -> Pour moi. But forcibly 'donated' to bro.
This kind of started it. Since then I have found a number of excuses to gift my friends and myself perfume. So, I bought -
Polo by Ralph Lauren -> My bro
Acqua di Gio by Giorgio Armani -> My other bro. And to a friend. Actually, my brother kindly decided that I should give it to him when I accidently broke the Givenchy bottle (which I had given him btw).
L'Eau Bleu by Issey Miyake -> Pour moi
Eternity by Calvin Klein -> Pour moi
A result of all these purchases and extensive trials (and tribulations) of other sundry brands has given me this extremely vague ability - I know an embarassingly large amount of information on perfumes. Woody, sharp, fruity, fresh. Day, casual, formal, night. I can tell any cologne. I can give expert advice. "Ahh..Hmm..You should go for a blah". I am fully aware that this a totally useless skill. Now, if I could name female perfumes - ahhh!

Hmm.

I put up an arbit post. In hindsight, it was arbit. Hence removed. But, thinking again I have put it up :D. Good or bad. Something. It has the words - Indian, Tamil, Brahmin, and Girls in it. I got a lot of it hits from people who searched for Indian Girls. More interesting posts coming up. Hopefully.

ACIDity and Qian Wang

I actually wanted to put up a philosophical post, but I have way too much going on right now to feel philosophical. I need to relax. R. E. L. A. X. I am sorely tempted to elicit some sympathy by listing out all the things I need to be getting done. I shall not. Why bug you poor souls also??

1. I have been spending the weekend poring over assorted books. For a database to be of any practical use it needs to have the ACID property over transactions performed on it.

Atomicity : A transaction is an atomic unit of processing. It is either performed entirely or not.
Consistency : A transaction is should be consistency preserving. It's complete execution should go from one consistent state to another.
Isolation : That is, the execution of a transaction should not be interfered with by any other transactions executing concurrently.
Durability : A commited transaction should not be lost. Durability is ensured through the use of transaction logs that facilitate the restoration of committed transactions in spite of any subsequent failures.

Boring no. Now do this - replace transaction with relationship. Big word. I feel very uncomfortable using it. Anyway, he he he. Now read it again. The perfect manual. Short. Succint. Simple. Can be (and should be) taught to every 6th standard kid. The final result - 80% reduction in teenage, middle age and old age angst, 70% reduction in quarter-life and mid-life crises - worldwide. The world IS a happier more beautiful place. It can be called Ramani's ACID Rule. You can put things to the ACID test. Since it's my rule, the RA(N)CID test. Hope it doesn't leave a bad taste in the mouth.

2. Have you noticed Chinese names. They are short. Chen. Liu. Wang. I think it's a very bad design idea. Try mistyping Subramaniam Anantharamakrishnan. What are the chances that you are going to create another valid name? akjaklsdj lkjasdklfjklasdjf. Now mistype Wang - Yang, Lang, Qang - all very plausible names. See, this creates huge problems.

Assuming you want to name your kid, and you tell the guy in the registrar office, your kids name, he mistypes, and instead of Qian Wang you have Qian Yang. It's a valid name. So, later you notice - oops mistake - and you cannot even tell the guy to change it. He will be like - "What, this name valid is. What you say. You me cheat". That was a lame imitation. Apologies.

I was thinking, there would be about 10,000 possible names with 5 letters. In a population of 1.5 billion, about 150000 people will share the same name. Assuming some names are more popular (which mean money, or wisdom or useful things like that), there is potential for almost a million people to share the same name. Do you know what that means?? It's horrendous searching for a guy on the net. It's time for them to increase the address space. They should be a convention where they decide to give everyone longer names. Consciously.

Note : No Chinese were offended in the creation of this joke. I quite like them actually. IF I could pronounce those names. You could learn to here.

Explanatory notes :D :D :

2) Try mistyping Subramaniam Anantharamakrishnan. What are the chances that you are going to create another valid name?

What I am saying is that if the name is long there is not a much of a chance for a mistype to lead you to another real person. But with short names, not so much. I can make a more 'profound' explanation, but it would scare everyone away. God knows why I am writing such geeky stuff. Maybe the semester has started and there is more geeky stuff occupying mindspace.

It's time for them to increase the address space. They should be a convention where they decide to give everyone longer names.

This is a terrible one. It's a take on the IPv6 convention when the internet was running out of doman addresses. So, they lengthened the length of each address so that there was enough for everyone. :D

Hmm..

In sooth, I know not why I am so sad:
It wearies me; you say it wearies you;
But how I caught it, found it, or came by it,
What stuff 'tis made of, whereof it is born,
I am to learn;
And such a want-wit sadness makes of me,
That I have much ado to know myself.

These opening lines I have remembered for the last 7 odd years. They had a nice rhyme, rhythm and they stuck in my head. And, I had studied that book so many times. So many. Never really thinking too much.
No wonder he has found appeal across the centuries. He appeals at a basic human level. It's not about the story, it's not about the location, it's not about the history. It's about the people. People don't change.

Coming soon...

I have been thinking what to write. Many categories sprung up (boing) -
1) Funny - Silly anecdotes from my non-existent life. More sillyness can follow but it could look silly.
2) Intellectual - The economics of gangs. I should follow it up with commentary on Greenspan's policy on interest rates. Very interesting.
3) Rant - There has been a sudden change in weather. It's been raining for the last few days - it's cold, wet, damp and generally highly irritating. My tennis is spoilt. Bah.
4) Philosophical - See this is interesting. In the policy of renunciation. Suffering stops with attachment. Lack of attachment. So, I shall disconnect myself from the worldly problems that so weigh us down and philosophize. Philosophy bakes no bread, but without philosophy you remain half baked. That was an orignal Ramani quote.
So coming up....a good old funda session. Preaching. Instructing. Educating. And boring. No not boring. Exciting. Very exciting.

The Economics of Gangs

You must read this article. It's fascinating. Fascinating. No other word. There is no hardcore math. There is no impossible to understand jargon. Well, it has some slightly difficult to understand jargon. But, nothing you can't figure out. I know jackshit in Economics and it made sense to me. So, read it and enjoy!

An Economic Analysis of a Drug-Selling Gang's Finances

It has tree diagrams in it where the don is at the top of the tree and called 'Central Gang Leadership' and gives into leaves called 'Enforcer','Treasurer' and 'Runner'. Below the 'Enforcer' there are 'Foot-soldiers'. It's kind of written in a dispassionate way. I find it amusing.

"..Given the relatively low economic returns to drug selling, the implied willingness to accept risk on the part of the participants is orders of magnitude higher than is typically observed in value of life calculations. That suggests that gang members have very unusual preferences, that the ex post realization of death rates was very different then the ex ante expectation, systematic miscalculation of risk, or the prescence of important noneconomic considerations."

"Morever, the violence keeps customers away. This negative shock to demand is associated with a fall of 20-30 percent in the price and quantity of drugs sold during fighting. In spite, of thus the gang discussed in this paper fights with rivals roughly one fourth of the time."

In the first, he is just trying to say that some stupid niggars are getting their ass shot up. In the second, he actually gives economic considerations why gang wars are not good for 'business'. It also looks at the dynamics of these wars - average duration, territory conquered and so on. According to him, crime doesn't pay - in a fundamental economic way. The average gangster earns about 15,000$ a year, about half the national average. Its the anticipation of future earnings which motivates. A very well written piece.

Anyway, I happened to come upon it during some random browsing. It's by Steven Levitt. He is a Professor of Economics at the University of Chicago. He won the the John Bates Clark Medal in 2002 given to promising economists under 40. A number of those went on to win the Nobel Prize in Economics. This article has a co-author Sudhir Alladi Venkatesh. Indian. There is an Indian Physicist called Alladi Ramakrishnan (he started Institute for Mathematical Sciences, in Taramani, behind IIT), I was wondering if it's his son or relative. I won't be too surprised. If you feel like it, read this one is worth reading as well. Same guy. It gives the background to the first link I put up.

"Are we a family or a business : American Urban Street Gangs"

PS: How is this erudite type stuff? If it's painful I won't put up such stuff :D.

55 words

He kept thinking what to write. His mind was blank. He hadn't really done anything today. Morbid stuff was off his list. So was silly humor. And recollections of random conversations. And deep philosophy. That wouldn't fit into 55 words. And who wanted to read philosophy anyway? So, he wrote this. In 55 words. Just.
Kirthi tagged me. I haven't been checked out yet. Ok. Forgiveness.
Madhura, KP could follow. Negi ? Rat?

More Observations of a Specific Kind

Friend 1
(Pre- Hot Consulting Job)
Me: Bye bugger
He: Bye
(Post- Hot Consulting Job)
Me: Bye bugger
He: As much as I would like to talk to you, I need to go for lunch with a friend. I hope I can catch you later.
Me: Huh? ($%@##$#)
Friend 2
(Geek. I have always known him as such. Quoted from the last post.)
Me: 2 Ph. D.s ??
He: Yeah. He didn't time multiplex.
Me: ?? (....)
Friend 3
(Marketing a.k.a. paid to bullshit)
Me and a guy or two: So, how do we get people to join Utsav.
He: Friends, we re-christened IGSA as UTSAV primarily to infuse in it a sense of joy and fun. Please try and understand the name carries everything. Right from our events to Asha briefings make sure "Utsav" comes first. If we can put Utsav first we can levarage its identity and can broaden our scope.
Me: Okk. (So a pumpkin called a rose becomes a rose. If, you can leverage it's identity. And broaden it's scope.)
'Friend' 4
(...)<- preserving my efforts at decency in this public form.
Me: So, we have been friends for so long.
'Friend': Yes, I let you be my friend. It's not like I am going to say 'No no don't be my friend'.
Me:@#$@#@#@$
#@#@#$=Fill in the blanks. Any guesses? Special points for good ones.

Curious Observations of a Random Kind

1. My CS batch in IIT had 30 students. There were about 120 undergraduates in my department across all the years. There were about 180 in my hostel. There were about 400 across all disciplines in my year, about 2000 across all the 4 years. I knew most guys in my branch, my hostel, and some random people through this and that. Lots of people - atleast by face. Here in UIUC, the CS department takes in about 300 undergraduate and 100 graduate students each year. The department has atleast 1500 students as a whole. The university has atleast 25,000 students on it's rolls. I know about 20 people here. I meet about 5 on a daily basis. Sucks no. I fully agree.

2. I had a couple of situations over the last week that has called on my mostly lacking diplomatic skills. When someone asks you for your opinion on something should you be tactful or truthful? Tact saves the awkwardness but borders on being dishonest. Thus is life, but you might not be actually appreciated for being truthful. So, it's a vague situation to be in. What I actually, ended up doing is telling the truth and 'buffering' it, you know, that's how it is for everybody so it's ok.

3. 95% of my meetings with acquaintaces go like this :
Me: Hi
Acq: Hi
(some hi how are you talk)
Me: So, whom do you work with? What do you do for your research?
This previous question can be replaced with:
What courses are you taking this semester?
Where did you intern this summer?
What are your plans? MS or PhD? Tech or Non-Tech?
Acq: Blah
Acq: (Same question rephrased to me)
Me: Blah.
You have no idea how ingrained you are to this. I am wondering if it is always like this. Do certain sets of people keep talking about the same set of things. Maybe some people discuss Vivek Oberoi and Aishwarya Rai. Maybe some discuss cricket. Maybe some discuss good movies. Being in the last bunch would be fun.

4. The Indian Graduate Student's association had an introductory session. I was part of the organizing committe (Yay. Don't worry, you don't need any qualifications. Actually, the basic criterion is you shouldn't have any qualifications. If you did, you wouldn't be there. Ok. Forgive me.).We had a Mr and Mrs Utsav (that's what our org. is called - Utsav).
We had an attitude questionaire and one of the questions were:
'Whats a good line for an alien you meet in a bar?'
Some 3 guys wrote.'Aaja meri gaadi mein bait ja'. 50 cent has a song whose title means the same thing. But, it's not so politely phrased. It's not too tough to guess though.
Another question was:
'Say something bad about yourself'
This question was in jest. Just to see if you can say something bad about yourself. One girl actually wrote 'Nothing'. Heh. I just found something.
Another was a fill in the blank:
'Johnny johnny yes papa...'. You had to fill it in with some nonsense.
One of the replies was hilarious. '..hack into my email account no papa'.

5. There is a Professor in CMU, Eric Xing, who has done 2 Ph. Ds. One in Biochemistry and one in Computer Science. No, he didn't as a friend of mine says 'time multiplex'. For those non-geek souls, that means he didn't do both at the same time. Like pick a cunning thesis topic. He did one after the other. After. I was wondering how one could possibly motivate onself to do that? After, one Ph. D. itself I will be like 'Whew!'. One more a? No no.