It hasn't been proven, and there is no conclusive proof, so don't worry. They are theories and there is some evidence to suggest that those things could possibly be the case, but equally that evidence could mean something else entirely - perhaps something we haven't thought of yet.
The hologram thing (I think) comes from the black hole information paradox, black hole thermodynamics and string theory. I don't understand it well enough to explain it but either have a look at those things on Wikipedia (and then explain it all to me
) or perhaps someone who knows a lot more than me can explain it, but it seems to be a lot more complicated than just 'we're a holographic projection on the cosmological horizon of information contained in the event horizon of a black hole'. Or something. See, told you I didn't really understand... :-/
The multiverse thing is, I think, the idea that our universe is just one of many (infinite?) universes that were created, or do you mean the many worlds theory, which is an interpretation of quantum mechanics that says that every possible alternate history of the universe exists, so every time something happens, the possible outcomes all exist in separate universes.
In short, I don't know enough about any of this stuff to help really, sorry. But I like chatting about it and kind of hope someone will just put me right.
Portal 