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>A quote: "And at least some physicists have been phenomenally successful as fund managers. Indeed, the fund that is widely viewed as the most successful hedge

by yarou 14y ago

>A quote: "And at least some physicists have been phenomenally successful as fund managers. Indeed, the fund that is widely viewed as the most successful hedge fund of all time, the Medallion Fund, was run for twenty years by mathematical physicist James Simons–the same James Simons who lent his name to Chern-Simons theory, which has been studied extensively by string theorists." P Quant math is relatively easy to grasp, so much so that an undergraduate with some statistics and calculus background can understand it quite easily. >All the evidence suggests that the EMH is true, that markets are unpredictable, and all successes are chance successes. Markets are unpredictable, but people (read: rational, utility-maximizing investors) aren't. Generally there is a level of herd behavior that can be modeled.

lutusp 14y ago
> Markets are unpredictable, but people (read: rational, utility-maximizing investors) aren't. Generally there is a level of herd behavior that can be modeled. You're overlooking the fact that some of those modeled people are analysts who are also trying to model, and act on, the behavior of the mob. In fact, analysts constitute their own mob. :) That restores the EMH to its rightful place.
- iskander 14y ago
  A recursive process with chaotic feedback cycles certainly won't be predictable but I also don't know under what model it's efficient either.
  - lutusp 14y ago
    > A recursive process with chaotic feedback cycles certainly won't be predictable ... Not so -- chaotic systems are predictable, if one understands the system. Using "chaotic feedback" as an argument isn't particularly instructive, given that chaos theory is a study of predictable systems that happen to be extraordinary sensitive to initial conditions. > I also don't know under what model it's efficient either. Of course such a system is efficient, if by "efficient" we mean that it doesn't violate physical laws. For example, there are any number of chaotic systems in nature, but all of them conserve energy and angular momentum (among other things). That tells us that such a system is difficult to read, but entirely obedient.
    - iskander 14y ago
      >chaotic systems are predictable Sprinkle in any measurement uncertainty and you no longer know the initial conditions. Hence, real world chaotic systems are unpredictable. >by "efficient" we mean that it doesn't violate physical laws. So...an inefficient market is one in which all the participants are time travelers?
      - lutusp 14y ago
        > Sprinkle in any measurement uncertainty and you no longer know the initial conditions. Hence, real world chaotic systems are unpredictable. Which part of your answer replies to my statement? Chaotic systems are predictable. All one needs are the initial conditions. Circle the word you didn't understand and raise your hand. Nothing is more common than an organization which exploits public ignorance of the innate predictability of complex systems.

by yarou 14y ago

lutusp 14y ago

> Markets are unpredictable, but people (read: rational, utility-maximizing investors) aren't. Generally there is a level of herd behavior that can be modeled. You're overlooking the fact that some of those modeled people are analysts who are also trying to model, and act on, the behavior of the mob. In fact, analysts constitute their own mob. :) That restores the EMH to its rightful place.

iskander 14y ago
A recursive process with chaotic feedback cycles certainly won't be predictable but I also don't know under what model it's efficient either.
- lutusp 14y ago
  > A recursive process with chaotic feedback cycles certainly won't be predictable ... Not so -- chaotic systems are predictable, if one understands the system. Using "chaotic feedback" as an argument isn't particularly instructive, given that chaos theory is a study of predictable systems that happen to be extraordinary sensitive to initial conditions. > I also don't know under what model it's efficient either. Of course such a system is efficient, if by "efficient" we mean that it doesn't violate physical laws. For example, there are any number of chaotic systems in nature, but all of them conserve energy and angular momentum (among other things). That tells us that such a system is difficult to read, but entirely obedient.
  - iskander 14y ago
    >chaotic systems are predictable Sprinkle in any measurement uncertainty and you no longer know the initial conditions. Hence, real world chaotic systems are unpredictable. >by "efficient" we mean that it doesn't violate physical laws. So...an inefficient market is one in which all the participants are time travelers?
    - lutusp 14y ago
      > Sprinkle in any measurement uncertainty and you no longer know the initial conditions. Hence, real world chaotic systems are unpredictable. Which part of your answer replies to my statement? Chaotic systems are predictable. All one needs are the initial conditions. Circle the word you didn't understand and raise your hand. Nothing is more common than an organization which exploits public ignorance of the innate predictability of complex systems.