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feat(RingTheory/Ideal/Height): prime ideal determined by height among overideals#36789

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hommmmm:eq-height-ideal
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feat(RingTheory/Ideal/Height): prime ideal determined by height among overideals#36789
hommmmm wants to merge 2 commits intoleanprover-community:masterfrom
hommmmm:eq-height-ideal

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@hommmmm hommmmm commented Mar 18, 2026

Summary

  • Add Ideal.eq_of_le_of_height_eq: a prime ideal of finite height is equal to any ideal of the same height that contains it.

Notes

This is a direct consequence of Ideal.height_strict_mono_of_is_prime: if I were strictly contained in J, their heights would differ.


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@github-actions github-actions bot added the new-contributor This PR was made by a contributor with at most 5 merged PRs. Welcome to the community! label Mar 18, 2026
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github-actions bot commented Mar 18, 2026

PR summary 316a0377d0

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference

Declarations diff

+ Ideal.eq_of_le_of_height_eq
+ Ideal.eq_of_le_of_height_le

You can run this locally as follows
## summary with just the declaration names:
./scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.


No changes to technical debt.

You can run this locally as

./scripts/reporting/technical-debt-metrics.sh pr_summary
  • The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
  • The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

@github-actions github-actions bot added the t-ring-theory Ring theory label Mar 18, 2026

/-- A prime ideal of finite height is equal to any ideal of the same height that contains it. -/
lemma Ideal.eq_of_le_of_height_eq [I.IsPrime] [I.FiniteHeight]
(J : Ideal R) (h : I ≤ J) (hIJ : I.height = J.height) : I = J :=
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You can probably generalize this J.height <= I.height?

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Done!

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I wouldn't keep this around anymore since it's an immediate specialization of the previous.

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