Perhaps, space {multiverse} has separate independent universes, with different phases. Perhaps, multiverse is still making and ending universes.
Level I multiverse
If space is infinite (or sufficiently large), and matter has even spatial distribution, universe objects and events repeat {Level I multiverse}.
Level II multiverse
Perhaps, if Level-I-multiverse universes are infinite in number, each universe has different dimension numbers and physical constants {Level II multiverse}. In string theory, quantum-field inflatons make space expand. For small quantum-field fluctuations, local bubbles form in universes. For example, if space starts with nine dimensions, only three expand, Alternatively, matter is in only three dimensions. Local bubbles become different universes, with different properties. Space inflation continues, making distances between bubbles expand faster than light, so universes are separate. Perhaps, vibrations between parallel three-dimensional universes along fourth dimension create and destroy universes. Perhaps, universes begin and end at black holes.
Level III multiverse
In quantum-mechanics many-worlds interpretation, all possible events occur (with different probabilities), making universe branches, which repeat {Level III multiverses}, and so do not become infinite in number. Observers see only one world by decoherence. All possible worlds are wavefunction-solution superpositions. Number of universes does not increase exponentially as time goes forward but stays constant, because they only repeat.
Level IV multiverse
Universes can vary in physical laws. Perhaps, all possible mathematical structures and universes exist {Level IV multiverse}.
Physical Sciences>Astronomy>Universe>Cosmology>Theories
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Date Modified: 2022.0224