You are suggesting possible future events that would provide evidence for a multiverse. That does not make something a falsifiable theory.<p>Analogy: it could happen that tomorrow Jesus Christ descends from the heavens and brings the day of reckoning. That would prove Christianity to be true, but the fact that this could happen does not make Christianity a falsifiable theory.<p>A falsifiable theory is a theory that predicts something that we can (in theory) measure today (possibly requiring infinite resources etc).<p>Your second example (which is not a multiverse theory at all) is actually a good example of a falsifiable theory. People have calculated [1] that if spacetime was folded back onto itself at even just a single point, it would leave a distinct signature in the cosmic microwave background. We do not observe this signature, so we are pretty sure spacetime does not fold back onto itself.<p>[1] <a href="http:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;1108.2842" rel="nofollow">http:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;1108.2842</a>