The CM example contains two “logical consequences” of your current state—two places that logically depend on your current decision, and so are “glued together” decision-theoretically—but the other “consequence” is not the you in heads-universe, which is occupying a different information state. It’s whatever determines Omega’s decision whether to give you money in heads-universe. It may be a simulation of you in tails-universe, or any other computation that provably returns the same answer, UDT doesn’t care.
Wait, you said:
But in the CM example, you did learn which it is. I am confused.
The CM example contains two “logical consequences” of your current state—two places that logically depend on your current decision, and so are “glued together” decision-theoretically—but the other “consequence” is not the you in heads-universe, which is occupying a different information state. It’s whatever determines Omega’s decision whether to give you money in heads-universe. It may be a simulation of you in tails-universe, or any other computation that provably returns the same answer, UDT doesn’t care.