Ring with Unity has Prime Ideal

Theorem

Let $A$ be a non-trivial commutative ring with unity.

Then $A$ has a prime ideal.

Proof

By Krull's Theorem, $A$ has a maximal ideal.

By Maximal Ideal of Commutative and Unitary Ring is Prime Ideal, $A$ has a prime ideal.

$\blacksquare$

Also see

• Spectrum of Ring is Nonempty