Relation which is not a function

Viewed 2k times. Evan Kim Evan Kim 2, 10 10 silver badges 23 23 bronze badges. This is how my professor wrote the question down. Add a comment. Active Oldest Votes. Alex Ortiz Alex Ortiz So in a way, a function is basically a subset of a binary relation! The defining feature of functions is that corresponding to each element of the domain, is a unique element in the codomain.

I corrected the example and also added one more example of a relation that is not injective. Sign up or log in Sign up using Google.

Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. Upcoming Events. Featured on Meta. Now live: A fully responsive profile. The unofficial elections nomination post. Related 2. Hot Network Questions. We can also represent a relation as a mapping diagram or a graph. For example, the relation can be represented as: Mapping Diagram of Relation Lines connect the inputs with their outputs.

The relation can also be represented as: Graph of Relation. In the relation , y is a function of x , because for each input x 1, 2, 3, or 0 , there is only one output y. To check if a relation is a function, given a mapping diagram of the relation, use the following criterion: If each input has only one line connected to it, then the outputs are a function of the inputs.

Example : In the following mapping diagram, y is a function of x , but x is not a function of y : Line Test. SparkTeach Teacher's Handbook.