Bitshares relies on users to designate mutually agreeable arbitrators (or escrow agents can't remember the name used), who can decide whether to reverse fraudulent transactions.
Mutually agreeing on an oracle = user-designated trust.
Ultimately these arbitrators link bitshares to the real world. Without the arbitrators, bitshares is completely virtual and there is no reason to expect it to have any relationship with real world behavior.
Just a quick piece of feedback - the pdf is fairly poorly formatted which makes it extremely hard to read. You might want to at least make the page margins smaller.
A brief look through and I see use of a fixed parameter - '7 months' - how did you arrive at this value?
The big distinction between hops and bitshares/mastercoin/ripple/etc. is that there is no use of trust relationships in any part of the system.
As with bitcoin, users are asked to trust in a system of economic incentives established by the protocol itself.
I might have missed something but where is the use of trust relationships in Bitshares?
Thanks. I am horrible/lazy at formatting. Will retype it in word when I get the chance. Thank you for your patience.
Yes, 7 months is a magic number. There are several magic numbers in the paper. In many cases, the justification is simply that it is easier to impose a number than design a voting or market-based selection mechanism. I opted for simplicity unless I saw something as mission critical. Here is the story behind 7 months (other magic numbers may have similar backstories):
It takes time for the hops backing hopdollars to respond to price changes, so in the short-run the current level of backing provides information about future levels of backing.
To avoid gaming, you need to use a time point far enough in the future that, given future prices, the current level of backing has no additional information about the future backing level.
I simulated adjustments to maintain parity with bitcoin using historical bitcoin price data.
See the graph here:
http://imgur.com/dJ2ekUuI arbitrarily imposed a starting disparity between the current backing level and the backing necessary to maintain parity with 1 USD. I then let the system run, assuming that users vote so as to target parity in a 30 day time frame (sooner if they are within 20% of parity). Using this algorithm, I find that a 3 month interval is sufficient to decouple the current backing level from the future backing level (i.e. starting state no longer matters for the ending state; only future price movements matter). This works even for an extremely large mismatch (say a factor of 10^9). I then added 4 extra months as a safety margin just in case real world behavior fails to outperform my algorithm.
I omitted this type of discussion from the paper to prevent it from becoming too long to read.