A true AIXI can’t model itself at all. A real AIXI variant (such as AIXItl) will not be able to model itself except in the rarest circumstances. Therefore its model of the universe as containing A is not going to be a simple one, because it can’t model A’s outputs. Therefore it seems that it will always be unable (as you said in another comment) to “recompute its inputs from the environment”.
I can’t model myself (or other humans) at all either, and yet I can still learn a model in which human behavior results from physical law, and make predictions on the basis of that model.
A true AIXI can’t model itself at all. A real AIXI variant (such as AIXItl) will not be able to model itself except in the rarest circumstances. Therefore its model of the universe as containing A is not going to be a simple one, because it can’t model A’s outputs. Therefore it seems that it will always be unable (as you said in another comment) to “recompute its inputs from the environment”.
I can’t model myself (or other humans) at all either, and yet I can still learn a model in which human behavior results from physical law, and make predictions on the basis of that model.