Alternative A! Alternative A generates the IOU Prices by subtracting the value of the best outcome from the others, and multiplies the result with -1.

The problem with Alternative A is that it would not interface well with other agents who might use a different game state evaluation formula. If another formula is used that gives Net Effect values of a magnitude ten times larger than the ones in the example, the IOU price for voting ';red;' would be 1 IOU instead of 0.1 IOU, a substantial increase. This means that some sort of normalisation is required.

Alternative B! Alternative B values an IOU as being the price to make the Negotiator vote in a way that is neutral to itself. That is, if there is a vote option that would not change the value of the board, it would take 1 IOU to make the Negotiator vote for that option. As always, the Negotiator's best option will have a price of 0 IOU. These two points makes up a linear scale from which we can generate the prices for all other vote options.

Alternative B has the attractive quality that harmful vote options would have IOU prices of over 1 IOU. Unfortunately this method is very sensitive to what the best option is. The normalisation factor is {$ \frac{1}{bestNetEffect} $}. Clearly a best net effect of zero would cause serious problems. There is also no guarantee that in a given election there is a single vote option that would generate a positive net effect, in which case the normalisation factor would be negative, resulting in negative IOU prices.

Alternative C! Alternative C values an IOU in a given election as being the price it would take to make the Negotiator vote for a vote option which would result in a game state value that equals the expected value of the next game state if the outcome had been randomised. This alternative has worked well in practice and avoids the problems apparent in Alternative A and B.

To calculate the price of a vote option with a net effect of x using this method in an election with best possible net effect equalling b and the mean net effect equalling m, the following formula would be used:

{$ IOU\, Price=1-\frac{x-m}{b-m} $}

Phase 1: Request/Provide Prices

As soon as the Initiation phase is complete, and the IOU prices have been generated, the Negotiator FSM makes a transition into the Uncommitted state. At this point the agent has not initiated or accepted any deals yet. The first step in doing so is to request the IOU prices of the other agents for the Negotiator's own favourite options, i.e. the vote options it has priced at 0 IOU. It does not concern itself with trying to create any deals for vote options it does not hold as being the best option available.

Fig(The-IOU-Negotiation-IP) shows the entire IOU-IP. The Request/Provide Prices sub-IP consists of messages 1 and 2.1-2.4.

Outgoing CFP (1)! The first message that is sent in the IOU-IP is a CFP (1) ACL Message asking the voters in the current election to provide the Negotiator with the IOU prices for its favourite vote options. One message is sent per voter and per favourite vote option. There may be several favourite options if they all result in the same, highest, net effect.