I have just recently started learning about inflationary cosmology so I don't know much about it. But from my understanding, the theory says the big bang was started by the expansion of a small region by negative pressure in the backbone universe that all the other pocket universes expand in.
If this understanding is correct (please correct me if I'm wrong) then could a pocket universe randomly be birthed out of negative pressure in our universe to give us a pocket universe, within our universe?
If this can't happen why? There something different in the composition of our universe and that of the pocket universe backbone?