Question

prove that every infinite set has a countable subset​

Answer 1

Step-by-step explanation:

hope this helps you....

Answer 2

Step-by-step explanation:

Since S is infinite, S∖{f(0),…,f(n−1)} is non-empty for each n∈N. Therefore f[N] is infinite. To show that f is injective, let m,n∈N, say m<n. ... Thus f[N] is a countable subset of S.