Quote from: johnny211 on March 29, 2014, 03:56:32 AM

Quote from: JorgeStolfi on March 29, 2014, 03:54:08 AM

Who knows, perhaps there is only one arbitrage algorithm working between China and the West, with the exchange rate "6.10" hard-coded, and the owner did not notice that it has changed. Cheesy

Doubtful the guy would not notice someone arbing his coins away

That possibility seems rather unlikely, but since we are discussing it...

I don't see how he would notice the error. Say, his robot would buy some coins at Huobi for less than 6100 CNY and sell them at Bitstamp for more than 1000 USD; that way he would make more proft than he thought, but his robot would miss some opportunities: buying at 6180 would still be profitable but the robot would not think so. Or, conversely, the robot buys at slightly less than 1000 at Bitstamp and sells for slightly more than 6100 at Huobi; then he is actually losing money, but will only notice if/when he tries to withdraw any excess CNY at Huobi and exchange them for USD at the banks --- which he doesn't have to, since he can rebalance the two accounts by moving bitcoins, at the artificial rate of 6.10 CNY/USD that he himself established.

Note that once the coins are sold, he will not know or care about what happens to them; even if they are bought by another arbitrage robot who sells them back at the other exchange. (Trading fees will probably prevent a runaway loop there.)

So, on the balance, I think his buggy robot would just miss some opportunities, which a competitor could exploit; but he may never notice that.