Maximal Ideal WRT Filter Complement is Prime in Distributive Lattice
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. In particular: plenty throughout 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
Assertions
Let $\struct {S, \vee, \wedge, \preceq}$ be a distributive lattice.
Let $F$ be a filter in $L$.
Let $M$ be an ideal in $L$ which is disjoint from $F$ such that:
Then $M$ is a prime ideal.
Proof
Aiming for a contradiction, suppose $M$ is not a prime ideal.
Then by Prime Ideal in Lattice, there are elements $a$ and $b$ of $L$ such that
- $a \wedge b \in M$
- $a \notin M$
- $b \notin M$
Lemma 1
There do not exist $m$ and $n$ in $M$ such that $m \vee a \in F$ and $n \vee b \in F$.
$\Box$
Without loss of generality, we can thus suppose that:
- $\forall m \in M: m \vee a \notin F$
Let $N = \set {x \in L: \exists m \in M: x \le m \vee a}$.
Lemma 2
$N$ is an ideal in $L$.
$\Box$
Lemma 3
$M \subsetneq N$
$\Box$
Lemma 4
- $N \cap F = \O$
$\Box$
By assuming that $M$ is not a prime ideal, we have constructed an ideal $N$ properly containing $M$ that is disjoint from $F$.
This contradicts the maximality of $M$.
Thus $M$ is a prime ideal.
$\blacksquare$