# Boolean Prime Ideal Theorem

This article needs proofreading.Please check it for mathematical errors.If you believe there are none, please remove `{{Proofread}}` from the code.To discuss this page in more detail, feel free to use the talk page.When this work has been completed, you may remove this instance of `{{Proofread}}` from the code. |

This article needs to be linked to other articles.You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by adding these links.To discuss this page in more detail, feel free to use the talk page.When this work has been completed, you may remove this instance of `{{MissingLinks}}` from the code. |

## Theorem

Let $\struct {S, \le}$ be a Boolean algebra.

Let $I$ be an ideal in $S$.

Let $F$ be a filter on $S$.

Let $I \cap F = \O$.

Then there exists a prime ideal $P$ in $S$ such that:

- $I \subseteq P$

and:

- $P \cap F = \O$

## Proof from the Axiom of Choice

Let $T$ be the set of ideals in $S$ that contain $I$ and are disjoint from $F$, ordered by inclusion.

Let $N$ be a chain in $T$.

Then $\ds U = \bigcup N$ is clearly disjoint from $F$ and contains $I$.

Let $x \in U$ and $y \le x$.

Then:

- $\exists A \in N: x \in A$

By the definition of union:

- $x \in U$

Let $x \in U$ and $y \in U$.

Then:

- $\exists A, B \in N: x \in A, y \in B$

By the definition of a chain:

- $A \subseteq B$

or:

- $B \subseteq A$

Hence $U$ is also an ideal.

This article, or a section of it, needs explaining.of what, and whyYou can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by explaining it.To discuss this page in more detail, feel free to use the talk page.When this work has been completed, you may remove this instance of `{{Explain}}` from the code. |

Without loss of generality, suppose $A \subseteq B$.

Then:

- $x \in B$

Since $y$ is also in $B$, and $B$ is an ideal:

- $x \vee y \in U$.

By Zorn's Lemma, $T$ has a maximal element, $M$.

It remains to show that $M$ is a prime ideal:

Every Boolean algebra is a distributive lattice.

So by Maximal Ideal WRT Filter Complement is Prime in Distributive Lattice, $M$ is a prime ideal.

#### Axiom of Choice

This proof depends on the Axiom of Choice, by way of Zorn's Lemma.

Because of some of its bewilderingly paradoxical implications, the Axiom of Choice is considered in some mathematical circles to be controversial.

Most mathematicians are convinced of its truth and insist that it should nowadays be generally accepted.

However, others consider its implications so counter-intuitive and nonsensical that they adopt the philosophical position that it cannot be true.

## Proof from the Ultrafilter Lemma

We prove that the Boolean Prime Ideal Theorem is equivalent to the Ultrafilter Lemma in ZF.

This theorem requires a proof.You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by crafting such a proof.To discuss this page in more detail, feel free to use the talk page.When this work has been completed, you may remove this instance of `{{ProofWanted}}` from the code.If you would welcome a second opinion as to whether your work is correct, add a call to `{{Proofread}}` the page. |

## Proof from Stone's Representation Theorem for Boolean Algebras

We prove that the Boolean Prime Ideal Theorem is equivalent to Stone's Representation Theorem for Boolean Algebras in ZF.

This theorem requires a proof.You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by crafting such a proof.To discuss this page in more detail, feel free to use the talk page.When this work has been completed, you may remove this instance of `{{ProofWanted}}` from the code.If you would welcome a second opinion as to whether your work is correct, add a call to `{{Proofread}}` the page. |

## Motivation

The Boolean Prime Ideal Theorem is weaker than the Axiom of Choice, but is similarly independent of ZF theory.

It is sufficient to prove a number of important theorems, although such proofs are often more involved than ones relying on the Axiom of Choice.