Definition:Multiplicative Function on Ring

Definition
Let $\struct {R, +, \circ}$ be a ring.

Let $f: R \to \R$ be a (real-valued) function on $R$.

$f$ is a multiplicative function on $R$ :


 * $\forall x, y \in R: \map f {x \circ y} = \map f x \times \map f y$

That is, a multiplicative function on $R$ is one where the value of the product of two elements of $R$ equals the product of their values.