(December 2, 2017 at 11:34 am)Alex K Wrote: If you are talking cardinality (sizes of sets) then you can ask how big is a union of two disjoint infinite sets- then the answer is infinity. But then there is a whole hierarchy of infinities: the union of two countable infinite sets is again countable infinite. The union of a countably infinite set and an uncountably infinite one is again uncountably infinite.
I dare you to count out a countably infinite set. Go head, 1..2...3...4...
