To add, for hutzlibu and others like them: as soon as infinite sets (or sequences. See https://plus.maths.org/content/when-things-get-weird-infinit...) are involved math gets counter-intuitive.

In this case, at most one of these two a priori quite reasonable statements can be true:

- if set B is a strict superset of A, B is larger than A.

- if you can map the times in A to the items in B in 1:1 fashion, A and B have the same size.

Giving up the first is deemed less problematic than giving up the second (probably because that means giving up comparing sizes of infinite sets at all, but I’m not familiar enough with that to be sure about that)