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You
you didn't use my hint a ⊆ p1 = p.
continue the proof
Copilot
Okay, I will try to finish the proof of Lemma 5.7. Here is what I have so far:- Since p1=p, we have p1 ··· pr ⊆ p, and therefore (x) ⊆ p=p1 ··· pr.
- By the minimality of r, we must have r=1, since otherwise we could write (x) as a product of fewer than r prime ideals, contradicting Lemma 5.5.
- Hence, we have (x)=p1=p, which means that p is principal, as desired.
To complete the proof, we need to show that θα ⊆ 𝑂𝐾 for some θ ∈ 𝐾 \ 𝑂𝐾. Here are the steps:- Since p is principal, we can write p=(y) for some y ∈ 𝑂𝐾.
- Since α ⊆ p, we can write α=(y)β for some ideal β ⊆ 𝑂𝐾.
- Let θ=y/x, where x is the nonzero element of α we chose earlier. Note that θ ∈ 𝐾 \ 𝑂𝐾, since x is not in 𝑂𝐾 by assumption.
- We claim that θα ⊆ 𝑂𝐾. To see this, let z ∈ α. Then z=yw for some w ∈ β. Hence, θz=(y/x)(yw)=w ∈ 𝑂𝐾, since β ⊆ 𝑂𝐾. This shows that θα ⊆ 𝑂𝐾, as claimed.
Therefore, we have proved Lemma 5.7. 🎉
I hope this helps. Do you have any questions or comments about the proof? I am happy to assist you. 😊 |
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