Replicate the success of Shrek?

http://www.apple.com/trailers/dreamworks/monstersvsaliens/

Michael Rabin

I have only one word to say about Michael Rabin's violin skills: impeccable. 

深交所

I admire those who start things from zero. Divide and conquer, this is real fun. 

http://www.chinavalue.net/Article/Archive/2005/11/7/13342.html

打油诗

一杯茶，一包烟，一支烂股盯半天

一分钱，一份闲，一批散户套半年

Rounding tricks

number theory day. another problem for fun. 

think about the bank. their system is with a minimal unit: 0.01, or, a cent. So any more decimal places would be rounded using the most common rule: 0-4, round down; 5-9, round up. 

so think about the following two scenarios:

1. Bank lends 0.1 to A, charging 6.31% annually. This 0.1 comes from two resources, a 0.05 deposit from B and the left 0.05 deposit from C. The deposit rate, for simplicity, also assumed to be 6.31%. Then what would be left in the bank after one year?

Not zero. The correct answer would be: (RND means round the number)

RND{ 0.1 * ( 1 + 6.31% ) } - 2 * RND{ 0.05 * ( 1 + 6.31% ) } = 0.11 - 2 * 0.05 = 0.01 

Well, you can say it's trivial. Who would give a damn to the 1 cent, especially for the bank. So let's see another example:

2. You have 160,000 to deposit into a bank with 3.14% annual deposit rate. What would you expect?

The answer may not be the most common one: 160,000 * ( 1 + 3.14% ) = 165,024. Let me show you another trick.

You split your money into pieces each with identical amount: 0.16. So for each piece, the finaly amount after a year would be RND{ 0.16 * ( 1 + 3.14% ) } = 0.17. Thus you would get 0.17 * 10^6 = 170,000. Compared with previous 165,024. An extra 4,976 is in your pocket. And that equals to a 6.25% annual rate. 

Of course, there are many limits in the bank. And my example is not to teach you to arbitrage, but to show you how a badly designed system could damage. 

I won't bother to explain the math after the two examples. Just for fun. 

Little problem for fun

just watched a video talking about Euler and his works. so post a little problem for fun in memory of this great mathematician. 

given a series of digits within {0,1,...,9} and operators to be taken in {+,-,*,/}. you can use () to change order arbitrarily. the ultimate goal is to form an equality between the left and right sides. 

a few examples:

22 => 2=2

235 => 2+3=5

4221 => 4/(2+2)=1

rules:

1. there must be one and only one operator between two consecutive digits. so 4*6=24 is illegal. 

2. there might be multiple some equalities, like 2221 => 2/2=2-1, 2-2/2=1. it's ok. as long as you can find one. still count as one.  

so here comes the problem. given a 2-digit pair, of course there are only 10 such equalities. then what about 3-digit, 4-digit, 5-digit? and what about 100-digit? how many serials we can find such equalities?

just a problem for fun. anyone who sends the answer (with a reasonable logic other than brute force) will win a good gift.

thanks for playing. 

Oh, man, it's so funny

Decode IBFX contest (I)

IBFX is holding a contest for its mini account which requires a min 250 deposit. The contest is calculated each month based on percentage return. Top 5 would be awarded cash directly. 

Several interesting thing can be observed from the historical results. 

1. The top 5 or so usually would dramatically outperform the other guys. They usually would at least double their assets. The top 100 can at least have a 10% return. 

2. There are always guys who blow up their whole assets. Even worse, someone can lose more than they have. This may be due to a terrible bet on the Friday close. 

3. If the contest participants can be viewed as rational sample of the traders at IBFX. Then definitely the broker woule earn a considerable amount from both spread taking and holding the opposite portfolios to the traders'.

Plateau

At triple point, finally there shows some stagnation. Is this because of human weaknesses or over exploration of my profitable patterns? In either case, time to do some review and summary.

Break, we need. 

Is now the right time to buy corporate America?

The election of Obama may not appear as beautiful as it seems. Too many and too chaotic expectations are put on him. But from another angle, as the old wall street saying goes, timing is everything. Obama knows this well. There is still room for the downside of American economy. But waiting for another 4 years probably would cost his opportunity to become Roosevelt. Risk is there, but the reward is pretty lucrative.

If we view the election as trading, then it's just a game that you can only access at limited openings. What's more, your opponent would only make you more risk seeking.

It's not the right time to buy America now. But for Obama, I would say he is lucky to be chosen at this historical time.