## Subset: a set contained in a set

Two weeks ago, we have talked about the basics of sets. In this post, we are going to talk about subsets.

In mathematics, if and are sets, we say that is a subset of , denoted by , if all elements of are also elements of . The easiest way to illustrate this is through a Venn diagram as shown on the right. In the Venn diagram, set is within set . Therefore, all elements of set are also elements of .

*Example 1*

Let be set of all letters in the English alphabet and be the set of vowel letters. It is clear that since {*a*, *e*, *i*, *o*, *u} *are elements and also are elements of . » Read more