I'm not sure what you're trying to say when talking about many instantiations. I am imagining all the extant machines synchronise their inputs and so there is only one AIXI instance. The input is some kind of concatenation of the sensory inputs of all of the machines with some kind of blank for nonfunctioning sensors. If I also considered scenarios where the communication lines can be cut the agent would be forced to split into more than one instance, and then it would not be so clear how or weather the agent can learn the reasonable intelligent behavior, which is why I did not consider that.