Sunday, April 19, 2009
Tuesday, April 14, 2009
1. Had a game theory class from 1 pm to 5 pm. I even could not formulate my question when Jörgen said, 'you look puzzled, ruixue'...
Too much to learn!
2. Read a methodology paper for tomorrow's Econ&Philosophy seminar on the subway back.
Too much to learn!
3. Had a Swedish class from 6 pm to 9 pm.
Too much to learn!
4. Got an email from a classmate's girlfriend who asked me to write a research proposal on public finance for her because she is applying somewhere.
I am too ignorant to help her!
Too much to learn!
2. Read a methodology paper for tomorrow's Econ&Philosophy seminar on the subway back.
Too much to learn!
3. Had a Swedish class from 6 pm to 9 pm.
Too much to learn!
4. Got an email from a classmate's girlfriend who asked me to write a research proposal on public finance for her because she is applying somewhere.
I am too ignorant to help her!
1. Wrote a short story in Chinese yesterday and could not sleep after that. I decided to give it up. Literature is bad for my health...
2. Came across a book. A good textbook should be rigorous, concise and never short of intuition. This book is not good in the sense that it is not concise enough. But numerous examples and detailed explanations make it a good book to read before bed. Yes, I will read it instead of writing nonsense stories.
2. Came across a book. A good textbook should be rigorous, concise and never short of intuition. This book is not good in the sense that it is not concise enough. But numerous examples and detailed explanations make it a good book to read before bed. Yes, I will read it instead of writing nonsense stories.
Monday, April 13, 2009
Saturday, April 11, 2009
Easter Holidays 2
1. Watched Song of the exile (1990).
2. Took a walk at skogskyrkogården and took a few pics.
1. Watched Song of the exile (1990).
2. Took a walk at skogskyrkogården and took a few pics.
Friday, April 10, 2009
Easter Holiday 1
1. Watched Muddy River (1981).
2. Took a walk at skogskyrkogården.
3. Had a haircut. I dislike myself from head to toe...Sigh.
1. Watched Muddy River (1981).
2. Took a walk at skogskyrkogården.
3. Had a haircut. I dislike myself from head to toe...Sigh.
Thursday, April 9, 2009
1. Attended the first lecture of Behavior Economics II in the morning. There were only three students and one of us does not intend to take it. Reading experimental studies is an entertainment. So I will take this course.
2. Had lunch with Mark after the class. There is a type of person who will always be the center of a group wherever he is. That's him. What's funny is that our topics are always around his girlfriends whom I do not really know personally...
3. Read Van Damme's Chapter 2. I read very slowly and took some notes.
4. Watched La Ceremonie again. Obviously I am not the only one who is fascinated by the Papin sisters. Given the description of the murder, the best candidate would definitely be Chabrol if we want to find a director to make a movie based on the story. But I like Sister My Sister better.
2. Had lunch with Mark after the class. There is a type of person who will always be the center of a group wherever he is. That's him. What's funny is that our topics are always around his girlfriends whom I do not really know personally...
3. Read Van Damme's Chapter 2. I read very slowly and took some notes.
4. Watched La Ceremonie again. Obviously I am not the only one who is fascinated by the Papin sisters. Given the description of the murder, the best candidate would definitely be Chabrol if we want to find a director to make a movie based on the story. But I like Sister My Sister better.
Tuesday, April 7, 2009
1. I have a vague idea while reading Levine's paper...Let me name it Expectation Squared at this moment...I need to think more about it.
2. Googlebooks do not provide more chapters in Van Damme's book, so I searched and asked a Chinese student online who said that he has a copy. He kindly sent me several chapters. Surprisingly (or perhaps not considering the small world property), he told me that he knows me more than I know him. And later he told me he had a friend who is studying at Penn and was my classmate. Besides, the paper I discussed at UCL was written by his office mate...I am very happy to know him. Sometimes I feel I might fail to be an economist but I would like to be a friend of economists:)
3. Similarly, I would like to be a friend of writers although I am not one of them. I read the book/magazine yueran sent me more carefully today. It's an interesting experience as the young writers' worlds are so different from mine...
4. I always want to set up a blog about the moments when I think of Ingmar Bergman...
2. Googlebooks do not provide more chapters in Van Damme's book, so I searched and asked a Chinese student online who said that he has a copy. He kindly sent me several chapters. Surprisingly (or perhaps not considering the small world property), he told me that he knows me more than I know him. And later he told me he had a friend who is studying at Penn and was my classmate. Besides, the paper I discussed at UCL was written by his office mate...I am very happy to know him. Sometimes I feel I might fail to be an economist but I would like to be a friend of economists:)
3. Similarly, I would like to be a friend of writers although I am not one of them. I read the book/magazine yueran sent me more carefully today. It's an interesting experience as the young writers' worlds are so different from mine...
4. I always want to set up a blog about the moments when I think of Ingmar Bergman...
Monday, April 6, 2009
Notes on Testing Game Theory
This paper is a bit philosophical, I would say. It provides some criticism of experimental studies, which seem to be a fad these days. I enjoyed reading it for two reasons. First, it talked about some questions I had when I took Behavioral Economics I. The key message to me is that game theory is not a consequentialist theory. As Jörgen stressed in class, we need to be more careful about setting up plays and assuming preferences. Many experiments seem to say: look at my experiment, people do not play Nash equilibrium!!! But this argument may not be valid since we cannot say what the equilibrium is without carefully identifying the preferences. Jörgen suggested testing joint hypothesis even epistemic modes of games cannot be falsified. He also mentioned (in class) that we should be more careful when talking about fairness...(I really like this point.)
Game theory was first developed by mathematicians. I guess they do not care about these subtleties. Economics is a science of human beings anyhow and preferences become very very important in characterizing a problem.
Secondly, it represents basic terminologies of game theory clearly, in words instead of math.
I. Basic terminologies
Game: (N, A, fai, P, I, C, p, r, v)
Game Form: (N, A, fai, P, I, C, p)
Game Protocol: (N, A, fai, P, I, C, p, r)
N: the set of personal players.
Such a game is a mathematical object that contains as its basic structure a directed tree, consisting of a finite number of nodes (or vertices) and branches (or edges). A play, tao, of the game is a route through the tree, starting at its initial node and ending at one of the end nodes, w. A node k’ is a successor of a node k if there is play that leads first to k and then to k’. Moreover, each end node is reached by exactly one play of the game, and each play reaches exactly one end node.
…
The set of non-end nodes is partitioned into player subsets, and each player subset in turn is partitioned into information sets for the player role. In each information set, the number of outgoing branches from each node is the same, and the set of outgoing branches from an information set is divided into equivalence classes, the moves available to the player at that information, so that every equivalence class contains exactly one outgoing branch from each node in the information set. A choice in an information set is a probability distribution over the moves available at the information set. In the game with exogenous random moves, one of players is ‘nature’, and all information sets for this non-personal player are singleton sets with fixed probabilities attached to each outgoing branch.
Pure Strategy/outcome
A pure strategy for a personal player role is a function that assigns one move to each of the role’s information sets. The outcome of a strategy profiles is the probability distribution induced on the set of end-nodes, or on the set of plays.
Subform
In a given game form Ksai, let K_0 be the subset of nodes k such that (i) k is either a move by nature or {k} is an information set of a personal player; and (ii) no information set in Ksai contains both a successor node and a non-successor node to k. Each node k in K_0 is the initial node of a subform.
(Here Jörgen talked about the subtlety of defining a subgame, i.e. whether it is context-related or isolated at k. It seems to me that this argument shares the same spirit of non- consequentialism. See Binmore et al (2002).)
II Levine's theory and discussion
Is the linear function a super clever idea or an arbitrary assumption? Is it robust?
Can I think of a better option?:)
This paper is a bit philosophical, I would say. It provides some criticism of experimental studies, which seem to be a fad these days. I enjoyed reading it for two reasons. First, it talked about some questions I had when I took Behavioral Economics I. The key message to me is that game theory is not a consequentialist theory. As Jörgen stressed in class, we need to be more careful about setting up plays and assuming preferences. Many experiments seem to say: look at my experiment, people do not play Nash equilibrium!!! But this argument may not be valid since we cannot say what the equilibrium is without carefully identifying the preferences. Jörgen suggested testing joint hypothesis even epistemic modes of games cannot be falsified. He also mentioned (in class) that we should be more careful when talking about fairness...(I really like this point.)
Game theory was first developed by mathematicians. I guess they do not care about these subtleties. Economics is a science of human beings anyhow and preferences become very very important in characterizing a problem.
Secondly, it represents basic terminologies of game theory clearly, in words instead of math.
I. Basic terminologies
Game: (N, A, fai, P, I, C, p, r, v)
Game Form: (N, A, fai, P, I, C, p)
Game Protocol: (N, A, fai, P, I, C, p, r)
N: the set of personal players.
Such a game is a mathematical object that contains as its basic structure a directed tree, consisting of a finite number of nodes (or vertices) and branches (or edges). A play, tao, of the game is a route through the tree, starting at its initial node and ending at one of the end nodes, w. A node k’ is a successor of a node k if there is play that leads first to k and then to k’. Moreover, each end node is reached by exactly one play of the game, and each play reaches exactly one end node.
…
The set of non-end nodes is partitioned into player subsets, and each player subset in turn is partitioned into information sets for the player role. In each information set, the number of outgoing branches from each node is the same, and the set of outgoing branches from an information set is divided into equivalence classes, the moves available to the player at that information, so that every equivalence class contains exactly one outgoing branch from each node in the information set. A choice in an information set is a probability distribution over the moves available at the information set. In the game with exogenous random moves, one of players is ‘nature’, and all information sets for this non-personal player are singleton sets with fixed probabilities attached to each outgoing branch.
Pure Strategy/outcome
A pure strategy for a personal player role is a function that assigns one move to each of the role’s information sets. The outcome of a strategy profiles is the probability distribution induced on the set of end-nodes, or on the set of plays.
Subform
In a given game form Ksai, let K_0 be the subset of nodes k such that (i) k is either a move by nature or {k} is an information set of a personal player; and (ii) no information set in Ksai contains both a successor node and a non-successor node to k. Each node k in K_0 is the initial node of a subform.
(Here Jörgen talked about the subtlety of defining a subgame, i.e. whether it is context-related or isolated at k. It seems to me that this argument shares the same spirit of non- consequentialism. See Binmore et al (2002).)
II Levine's theory and discussion
Is the linear function a super clever idea or an arbitrary assumption? Is it robust?
Can I think of a better option?:)
I am very happy...because I just had a lecture of game theory with Jörgen...I should focus and write up something. Hopefully I can be a qualified teacher in the future so that I can have the courage to let him know how his courses have changed me. I was so tired of economics after spending 3 years at ccer and his beautiful math lectures reignited my enthusiasm. Now I am having a second course with him. I am really happy:)
Yinan told me he went to UCL to give a seminar and the response is very good. I am glad for him!
Yinan told me he went to UCL to give a seminar and the response is very good. I am glad for him!
Sunday, April 5, 2009
Hi, I am back. I was struggling with love these days but it is over now. I think I still love but I am not loved any more. I can only keep my love in my heart then. It's mine. I know being in and out of love is common among young people but I doubt whether I can love any one else. Nine years is not too long, but not too short either. God bless the beloved:)
I read Chapter 1 of van Damme's book. The book is very well written, and very difficult.
I read Chapter 1 of van Damme's book. The book is very well written, and very difficult.
Thursday, April 2, 2009
stata to LaTex
It's very easy and it will make your regression results good-looking!!!
Try outtex first:)
It's very easy and it will make your regression results good-looking!!!
Try outtex first:)
Wednesday, April 1, 2009
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