# Definition:Polynomial Ring/Universal Property

## Definition

Let $R$ be a commutative ring with unity.

A **polynomial ring over $R$** is a pointed $R$-algebra $(S, \iota, X)$ that satisfies the following universal property:

- For every pointed $R$-algebra $(A, \kappa, a)$ there exists a unique pointed algebra homomorphism $h : S\to A$, called evaluation homomorphism.

This is known as the **universal property of a polynomial ring**.