feat(RingTheory/Spectrum/Prime/Noetherian): rank of an Artinian ring over a field#38182
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tb65536 wants to merge 2 commits intoleanprover-community:masterfrom
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feat(RingTheory/Spectrum/Prime/Noetherian): rank of an Artinian ring over a field#38182tb65536 wants to merge 2 commits intoleanprover-community:masterfrom
tb65536 wants to merge 2 commits intoleanprover-community:masterfrom
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PR summary c4037aa6b4
|
| File | Base Count | Head Count | Change |
|---|---|---|---|
| Mathlib.RingTheory.Spectrum.Prime.Noetherian | 1783 | 1784 | +1 (+0.06%) |
| Mathlib.RingTheory.OrderOfVanishing.Noetherian | 2269 | 2270 | +1 (+0.04%) |
Import changes for all files
| Files | Import difference |
|---|---|
46 filesMathlib.AlgebraicGeometry.AffineSpace Mathlib.AlgebraicGeometry.AffineTransitionLimit Mathlib.AlgebraicGeometry.AlgClosed.Basic Mathlib.AlgebraicGeometry.Artinian Mathlib.AlgebraicGeometry.Fiber Mathlib.AlgebraicGeometry.Geometrically.Basic Mathlib.AlgebraicGeometry.Geometrically.Connected Mathlib.AlgebraicGeometry.Geometrically.Integral Mathlib.AlgebraicGeometry.Geometrically.Irreducible Mathlib.AlgebraicGeometry.Geometrically.Reduced Mathlib.AlgebraicGeometry.IdealSheaf.Functorial Mathlib.AlgebraicGeometry.IdealSheaf.IrreducibleComponent Mathlib.AlgebraicGeometry.Morphisms.ClosedImmersion Mathlib.AlgebraicGeometry.Morphisms.FinitePresentation Mathlib.AlgebraicGeometry.Morphisms.FiniteType Mathlib.AlgebraicGeometry.Morphisms.Finite Mathlib.AlgebraicGeometry.Morphisms.FlatDescent Mathlib.AlgebraicGeometry.Morphisms.FlatMono Mathlib.AlgebraicGeometry.Morphisms.Immersion Mathlib.AlgebraicGeometry.Morphisms.Integral Mathlib.AlgebraicGeometry.Morphisms.Proper Mathlib.AlgebraicGeometry.Morphisms.SchemeTheoreticallyDominant Mathlib.AlgebraicGeometry.Morphisms.Separated Mathlib.AlgebraicGeometry.Morphisms.UniversallyClosed Mathlib.AlgebraicGeometry.Morphisms.UniversallyOpen Mathlib.AlgebraicGeometry.Noetherian Mathlib.AlgebraicGeometry.PointsPi Mathlib.AlgebraicGeometry.ProjectiveSpectrum.Proper Mathlib.AlgebraicGeometry.QuasiAffine Mathlib.AlgebraicGeometry.RationalMap Mathlib.AlgebraicGeometry.Sites.ConstantSheaf Mathlib.AlgebraicGeometry.Sites.Fpqc Mathlib.AlgebraicGeometry.SpreadingOut Mathlib.AlgebraicGeometry.ValuativeCriterion Mathlib.RingTheory.AdicCompletion.Noetherian Mathlib.RingTheory.HopkinsLevitzki Mathlib.RingTheory.Ideal.KrullsHeightTheorem Mathlib.RingTheory.Jacobson.Artinian Mathlib.RingTheory.KrullDimension.Polynomial Mathlib.RingTheory.KrullDimension.Regular Mathlib.RingTheory.OrderOfVanishing.Basic Mathlib.RingTheory.OrderOfVanishing.Noetherian Mathlib.RingTheory.RegularLocalRing.Defs Mathlib.RingTheory.Spectrum.Prime.Jacobson Mathlib.RingTheory.Spectrum.Prime.LTSeries Mathlib.RingTheory.Spectrum.Prime.Noetherian |
1 |
Declarations diff
+ exists_not_mem_forall_mem_of_ne
+ finrank_eq_sum_primeSpectrum
+ instance : Fintype (PrimeSpectrum R)
- _root_.IsArtinianRing.exists_not_mem_forall_mem_of_ne
- instance : Finite (PrimeSpectrum R)
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
relativevalue is the weighted sum of the differences with weight given by the inverse of the current value of the statistic. - The
absolutevalue is therelativevalue divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).
tb65536
commented
Apr 17, 2026
Comment on lines
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| instance : Ring.KrullDimLE 0 R := .mk₀ fun _ _ ↦ inferInstance | ||
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| instance : DiscreteTopology (PrimeSpectrum R) := | ||
| discreteTopology_iff_finite_and_krullDimLE_zero.mpr ⟨inferInstance, inferInstance⟩ |
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These unnamed instances technically had their name changed from the namespace, but I assume that's fine given that the autogenerated names aren't supposed to be used anyway?
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This PR proves that the rank of an Artinian ring over a field is the sum of the ranks of the localizations.
This will be applied in #37130 to prove the ramification-inertia formula (this is where the sum first shows up).
I had to upgrade the Finite instance on the prime spectrum of an Artinian ring to a Fintype instance in order to write down the sum, but this should be fine since this fintype instance can already be inferred from heavier imports: https://live.lean-lang.org/#codez=JYWwDg9gTgLgBAWQIYwBYBtgCMBQOB2E%2BAxhOAK4xJboCmctAHkuHXAN4BKcAXHACoBPMLQBUAXzgBtAMJkQnYPgDmcTgF1pASQDOAQVhLgSfIpVrNfAGJKYw%2BgAoAClFC0AyiOIwo5EGoBKXgBeHDg4JQAzWigtfB0qElocIA