Chapter 2, Problem 1RQ

To determine

To explain:

One set is a subset of another set. Also, prove that one set is a subset of another set.

Explanation of Solution

A set $P$ is a subset of $Q$ if each element of $P$ is also the element of $Q$.

We have to show that $P$ is a subset of $Q$.

Suppose that $a\in P$.

Thus, $a\in Q$.

Therefore, $a\in P$ implies $a\in Q$.

So that $P\subseteq Q$.

Hence, $P$ is a subset of $Q$.