 Solution

ID: past-exam-of-the-year-1-of-the-computer-science-course-of-the-university-of-oxford/2014/discrete-mathematics-continuous-mathematics-and-probability/2/a/solution

List the

n

elements of the finite set

A

. A subset is determined by

n

membership decisions, each with two possibilities. This is a bijection from the power set to the set

{0, 1}^{n}

, so

∣ P (A) ∣ = 2^{n} .

The empty set case is included: its power set contains the single empty subset.

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