Question

Arrange the steps in the correct order to prove the theorem "If A and B are sets, A is uncountable, and A ⊆ B, then B is uncountable." Rank the options below.

a. Since A is a subset of B, taking the subsequence of {bn} that contains the terms that are in A gives a listing of the elements of A.
b. Thus B is not countable.
c. The elements of B can be listed as b1, b2, b3
d. Therefore A is countable, contradicting the hypothesis.

Answer 1

Explanation:

We are to rank the options given in the question to correctly prove the theorem that: "If A & B are set, and A is a subset of B"

To arrange the steps in the correct order, we have:

(a) Assume that B is countable

(b) The elements of B can be listed as b1, b2, b3

(c) Since A is a subset of B, taking the subsequence of {bn} that contains the terms that are in A gives a listing of the elements of A.

(d) Therefore A is countable, contradicting the hypothesis.

(e) Thus B is not countable