Sets and Venn Diagrams

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What is a Venn Diagram?


Everything inside the black outline of the rectangle is defined as the “universal set” or U.

Set U is the main set and then there are subsets.
The blue circle is one subset and the purple is another subset of U.


The Diagram


Each circle is a set representing its own collection of elements.

The purpose of the Venn diagram is to show the relationship between any two or more sets, usually using the overlapping of the circles.



How are Sets Related



Sets are said to be in union when they are overlapping, like at the right. Saying “union” includes all elements in A, B, or in both A and B.
To write A union B, it would be AUB

The section between the two sets, where elements are in A and B, is known as the intersection.