**ARTICLE I**

**Sets, maps, composition**

*A first example of a category*

Before giving a precise definition of ‘category’, we should become familiar with one example, the **category of finite sets and maps.**

An in this category is a finite *set* or *collection.* Here are some examples:

(the set of all students in the class) is one object,

(the set of all desks in the classroom) is another,

(the set of all the twenty-six letters in our alphabet) is another.

You are probably familiar with some notations for finite sets:

{*John, Mary, Sam*}

is a name for the set whose ...

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