Your linked result seems to talk about average utilities in the long run, which corresponds to a discount factor of 1. In the general case it seems to me that discount factors can change the outcome. For example, if the benefit of unilaterally defecting instead of cooperating on the first move outweighs the entire future revenue stream, then cooperating on the first move cannot be part of any Nash equilibrium. I found some results saying indefinite cooperation is sustainable if the discount factor is below a certain threshold.
That sounds reasonable. If v is the expected discounted utility at minmax, w the expected discounted utility according to the cooperative strategy, then whenever the gain to defection is less than w-v, we’re fine.
Your linked result seems to talk about average utilities in the long run, which corresponds to a discount factor of 1. In the general case it seems to me that discount factors can change the outcome. For example, if the benefit of unilaterally defecting instead of cooperating on the first move outweighs the entire future revenue stream, then cooperating on the first move cannot be part of any Nash equilibrium. I found some results saying indefinite cooperation is sustainable if the discount factor is below a certain threshold.
That sounds reasonable. If v is the expected discounted utility at minmax, w the expected discounted utility according to the cooperative strategy, then whenever the gain to defection is less than w-v, we’re fine.