Ultimately anything you can imagine is true in many universes that exist. let me share an ancient esoteric secret with you; things that do not exist, do not enter the mind.

Oh? Is there a universe where 1+1=3?

There could be... assuming that your reorder your digits for counting so they are arranged numerically in a different sequence, such as the following:

0 1 3 5 7 9 2 4 6 8

10 11 13 15 17 19 12 14 16 18

30 31 33 35 37 39 32 34 36 38

... etc ...

In this universe, since the numerical sequence is labeled differently, the following math operations would be true:

1 + 1 = 3

1 + 3 = 5

3 + 3 = 7

3 * 3 = 7

3 * 5 = 2

5 * 5 = 8

But why stop there... the digits would not have to be labeled after any digits that we are familiar anyway and you could end up with:

& + # = @