SETS AND INTERSECTION

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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