Question

Which condition must hold for a relation to be a function from \(A\) to \(B\)?

Options

• Every element of the codomain must be used.

• Every element of the domain must have two images.

• Every element of the domain must be used.

• The domain and codomain must contain the same elements.

Answer 1

For a function, every element of the domain must be used. An element of the codomain need not occur as an image of any domain element.