### Create an infinite set with list comprehension

Hello.
In Sage is possible to create B = Set(Primes()). For B Sage says Set of all prime numbers: 2, 3, 5, 7, ... . So B is infinite.
I try to create now a set C = Set([x^2 for x in QQ]). I am expecting to get something similar like above, but Sage does not get so far. After some 20 Minutes of waiting I broke down the action.
Is possible to create an infinite Set with list comprehension? I know that lists should befinite but the notation used by list
comprehension is very near on the mathematical way to describe a set like D = Set([x^2 for x in range(10)]) for example.
Any help appreciated.
Thank you and regards,
Vasile