[Merged by Bors] - refactor: unify the two versions of `pow_eq_one_iff` #30799

YaelDillies · 2025-10-22T19:25:49Z

One version is about torsion-free monoids, the other one about linearly ordered monoids. I argue that all linearly ordered monoids of interest are torsion-free, and therefore the correct lemma to keep is the former.

As a byproduct, I must move a few MonoidHom lemmas.

Zulip

depends on: [Merged by Bors] - feat(Algebra/Group/Torsion): characterise when a ^ n = 1 #30680
depends on: [Merged by Bors] - refactor: simplify InjOn univ f to Injective f #31024
depends on: [Merged by Bors] - feat(Finset): interaction of attach and cons #31025
depends on: [Merged by Bors] - feat: pullback PosMulMono #31026
depends on: [Merged by Bors] - chore: shortcut instance for Nat to be mul-torsion-free #31027
depends on: [Merged by Bors] - chore: rename isUnit_of_mul_eq_one to IsUnit.of_mul_eq_one #31283
depends on: [Merged by Bors] - refactor: make LinearOrderedCommMonoidWithZeros cancellative #31749

github-actions · 2025-10-22T19:27:13Z

PR summary 34d89e32aa

Import changes exceeding 2%

%	File
+57.61%	`Mathlib.Algebra.Ring.Torsion`

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.Algebra.Ring.Torsion	92	145	+53 (+57.61%)
Mathlib.RingTheory.Valuation.Basic	835	836	+1 (+0.12%)

Import changes for all files

Files	Import difference
86 files `Mathlib.Algebra.Order.Ring.Archimedean` `Mathlib.Algebra.Order.Ring.StandardPart` `Mathlib.AlgebraicGeometry.EllipticCurve.Reduction` `Mathlib.AlgebraicGeometry.ProjectiveSpectrum.Proper` `Mathlib.AlgebraicGeometry.ValuativeCriterion` `Mathlib.FieldTheory.Laurent` `Mathlib.FieldTheory.RatFunc.AsPolynomial` `Mathlib.FieldTheory.RatFunc.Degree` `Mathlib.NumberTheory.BernoulliPolynomials` `Mathlib.NumberTheory.Bernoulli` `Mathlib.NumberTheory.Cyclotomic.CyclotomicCharacter` `Mathlib.NumberTheory.FunctionField` `Mathlib.NumberTheory.Harmonic.Int` `Mathlib.NumberTheory.NumberField.FractionalIdeal` `Mathlib.NumberTheory.NumberField.Ideal.KummerDedekind` `Mathlib.NumberTheory.Padics.AddChar` `Mathlib.NumberTheory.Padics.HeightOneSpectrum` `Mathlib.NumberTheory.Padics.Hensel` `Mathlib.NumberTheory.Padics.MahlerBasis` `Mathlib.NumberTheory.Padics.PadicIntegers` `Mathlib.NumberTheory.Padics.PadicNumbers` `Mathlib.NumberTheory.Padics.ProperSpace` `Mathlib.NumberTheory.Padics.RingHoms` `Mathlib.NumberTheory.Padics.WithVal` `Mathlib.NumberTheory.RamificationInertia.Basic` `Mathlib.NumberTheory.RamificationInertia.Galois` `Mathlib.NumberTheory.RamificationInertia.Unramified` `Mathlib.RingTheory.DedekindDomain.AdicValuation` `Mathlib.RingTheory.DedekindDomain.Different` `Mathlib.RingTheory.DedekindDomain.Dvr` `Mathlib.RingTheory.DedekindDomain.Factorization` `Mathlib.RingTheory.DedekindDomain.FiniteAdeleRing` `Mathlib.RingTheory.DedekindDomain.GaussLemma` `Mathlib.RingTheory.DedekindDomain.Instances` `Mathlib.RingTheory.DedekindDomain.LinearDisjoint` `Mathlib.RingTheory.DedekindDomain.PID` `Mathlib.RingTheory.DedekindDomain.SInteger` `Mathlib.RingTheory.DedekindDomain.SelmerGroup` `Mathlib.RingTheory.DiscreteValuationRing.Basic` `Mathlib.RingTheory.DiscreteValuationRing.TFAE` `Mathlib.RingTheory.DividedPowers.Padic` `Mathlib.RingTheory.Flat.TorsionFree` `Mathlib.RingTheory.FractionalIdeal.Norm` `Mathlib.RingTheory.HahnSeries.Valuation` `Mathlib.RingTheory.Ideal.Int` `Mathlib.RingTheory.Ideal.Norm.AbsNorm` `Mathlib.RingTheory.Ideal.Norm.RelNorm` `Mathlib.RingTheory.KrullDimension.Regular` `Mathlib.RingTheory.LaurentSeries` `Mathlib.RingTheory.LocalProperties.Semilocal` `Mathlib.RingTheory.LocalRing.ResidueField.Polynomial` `Mathlib.RingTheory.Localization.AtPrime.Extension` `Mathlib.RingTheory.PowerSeries.Derivative` `Mathlib.RingTheory.PowerSeries.Ideal` `Mathlib.RingTheory.PowerSeries.Inverse` `Mathlib.RingTheory.PowerSeries.WeierstrassPreparation` `Mathlib.RingTheory.Trace.Quotient` `Mathlib.RingTheory.Valuation.AlgebraInstances` `Mathlib.RingTheory.Valuation.Archimedean` `Mathlib.RingTheory.Valuation.Basic` `Mathlib.RingTheory.Valuation.Discrete.Basic` `Mathlib.RingTheory.Valuation.ExtendToLocalization` `Mathlib.RingTheory.Valuation.Extension` `Mathlib.RingTheory.Valuation.Integers` `Mathlib.RingTheory.Valuation.Integral` `Mathlib.RingTheory.Valuation.IntegrallyClosed` `Mathlib.RingTheory.Valuation.LocalSubring` `Mathlib.RingTheory.Valuation.Minpoly` `Mathlib.RingTheory.Valuation.PrimeMultiplicity` `Mathlib.RingTheory.Valuation.Quotient` `Mathlib.RingTheory.Valuation.RamificationGroup` `Mathlib.RingTheory.Valuation.ValuationRing` `Mathlib.RingTheory.Valuation.ValuationSubring` `Mathlib.RingTheory.Valuation.ValuativeRel.Basic` `Mathlib.RingTheory.Valuation.ValuativeRel.Trivial` `Mathlib.RingTheory.Valuation.ValuativeRel` `Mathlib.RingTheory.WittVector.Compare` `Mathlib.RingTheory.WittVector.DiscreteValuationRing` `Mathlib.RingTheory.WittVector.FrobeniusFractionField` `Mathlib.RingTheory.WittVector.Isocrystal` `Mathlib.Topology.Algebra.Ring.Compact` `Mathlib.Topology.Algebra.Valued.ValuationTopology` `Mathlib.Topology.Algebra.Valued.ValuativeRel` `Mathlib.Topology.Algebra.Valued.ValuedField` `Mathlib.Topology.Algebra.Valued.WithVal` `Mathlib.Topology.Algebra.Valued.WithZeroMulInt`	1
`Mathlib.Algebra.Ring.Torsion`	53

Declarations diff

+ pow_eq_one_iff_left
+ pow_eq_one_iff_right
- IsMulTorsionFree.pow_eq_one_iff
- IsMulTorsionFree.pow_eq_one_iff_left
- IsMulTorsionFree.pow_eq_one_iff_right

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

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

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

No changes to technical debt.

You can run this locally as

./scripts/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).

mathlib4-merge-conflict-bot · 2025-10-23T17:08:44Z