Sets- a set in an unordered collection of distinct object. The object in a set are called ELEMENTS or Members of the set. A set is said to contain its element.
A set can be defined by simply listing its memmebrs inside the curly braces, for example the set {2,4,17,23} is the same as the set {17,4,23,2}.
If we want to specify a long sequence that follows a pattern we can use the elipsis notation- which means "Fill in using the pattern" the elipsis is often used after two or more members of the sequence and before the last one, as follows
{1,2,3,4.............n}
A U B={X/X ∈ A U X ∈ B
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SET ELEMENT OR/UNION
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SET ELEMENT OR/UNION
