This does not make any sense.

If there are an infinite number of fractions between 1 and 2, all you are doing is naming a set of universes with a constricted naming convention, and the set of universes is still infinite, thus contains any possible universe including an infinite number with an exact replica of you, an infinite number with a slightly different version of you, and an infinite number where you do not exist.

Just because constrained infinities of certain kinds of numbers can be nested within other infinities of unconstrained, or less constrained infinities of universes does not mean that somehow this has applications to multiverse theory.

If the given assumption is 'there are an infinite number of alternate universes' then the fact that fractions between 1 and 2 are an infinite set has literally no logical ability to mandate that this would somehow constrain the nature of previously established infinity of universes.

The possibilities of an infinite set of universes would be ultimately constrained by all possible sets of the laws of physics that allow any kind of universe to exist.

We already know that we live in a universe where humans exist, so, again, there will thus be an infinite number of universes with an infinite number of variations of you exist, and and infinite number where you do not exist.

EDIT: Here is maybe another way of looking at this.

There are an infinite number of positive integers.

There are also an infinite number of even integers, as well as odd integers.

The set of all odd integers contains half the number of all integers, though both are still infinite.

The set of all odd integers is constrained by the rule of none of its constituents are cleanly divisible by two.

But the fact that you can arbitrarily chose a rule to constrain one, larger infinite set into a smaller but still infinite set, does not mean that the larger infinite set does not still exist.

For this 'fractional universes' constraint to make any sense, one would have to demonstrate /why/ the constraint would need to apply to a set of all universes, in a way that is actually meaningfully different than /the constraint not being there/.

And that is an astoundingly complex matter of physics, not Set Theory 101.

EDIT 2: My above example from EDIT 1 is not logically valid, so... I played myself on that one, and worse it seems to have confused the whole discussion, so, apologies for that.

Check out leftzero's link for a more accurate analogy that I /should/ have used.

I still believe my original main point still stands though: The fact that there are an infinite number of fractions between 1 and 2 in no way means anything whatsoever about possible multiverses.

Possible and Impossible universes are defined by the laws of physics.

To override my comment elsewhere in this thread:

A universe without gravity could conceptually exist, but stars would not form, so we would probably not have any of the atomic elements produced by novae and super novae. Also, no galaxies, no black holes, no planets, no life as we know it, as it seems life requires a planet.

A universe without the Strong Nuclear Force would just be 'quark soup'.

A universe without the Weak Nuclear Force on the other hand has been demonstrated by at least one, perhaps now multiple papers to actually possibly be relatively similar to ours in some ways... very big picture kind of ways.

A universe without ElectroMagnetism ... at bare minimum would have vastly different Chemistry than ours. Organic Chemistry seems largely impossible, so no life as we know it, other than possibly some primitive extremophiles.

But these are just thought experiments.

My main point was the whole 'infinite fractions existing between 1 and 2 has no ramifications on multiverses that could exist' thing, and I again apologize for an incorrect and misleading example.