# Is {(1, 2); (2, 3); (3, 4); (2, 5)} a function?

##### 1 Answer

Jul 4, 2015

No it is not a function.

#### Explanation:

A function is a relation (a set of ordered pairs) with the additional property that: no two pairs have the same first element and different second elements.

The definition is often stated as: A relation in which every

**not** a function.

**Note**

**is** a function.

(It is ok to have different first elements and the same second elements. The definition of function is very precise.)