Documentation

TauCeti.NumberTheory.ArithmeticDirichletSeries.Weight

Completely multiplicative ideal weights #

The completely multiplicative specializations of TauCeti.IdealArithmeticFunction.

A TauCeti.MultiplicativeIdealWeight K is a monoid-with-zero homomorphism Ideal (π“ž K) β†’*β‚€ β„‚ killing only finitely many height-one primes, and TauCeti.UnitaryIdealWeight K is the subtype of those whose values have modulus 1 away from that finite bad set. Using Mathlib's β†’*β‚€ vocabulary is what pins the zero-ideal law Ο‡ βŠ₯ = 0; the finiteness condition is what bounds the bad local factors of the Euler product.

Both carriers are degree one: the value at 𝔭 ^ n is forced to be Ο‡ 𝔭 ^ n. They are therefore deliberately too narrow for the ideal MΓΆbius function or for coefficient systems whose prime-power values are independent local data; those get separate carriers.

The good ideals of a weight are the ideals prime to its bad primes in the sense of Ideal.IsPrimeTo (from TauCeti.RingTheory.DedekindDomain.Ideal): nonzero and divisible by no prime of the set. Its induction principle Ideal.IsPrimeTo.induction_on factors a good ideal into good primes; this is the engine behind both TauCeti.MultiplicativeIdealWeight.apply_ne_zero_iff_isGood and TauCeti.UnitaryIdealWeight.norm_eq_one.

Main declarations #

Negative results #

Two negative results delimit the carriers. TauCeti.MultiplicativeIdealWeight.coe_ne_const_one says the everywhere-one function on all integral ideals underlies no weight, because β†’*β‚€ forces the value 0 at βŠ₯ β€” the everywhere-one function on the nonzero ideals is the trivial weight instead (TauCeti.MultiplicativeIdealWeight.toIdealArithmeticFunction_one). TauCeti.UnitaryIdealWeight.norm_normTwist_apply_ne_one says that a norm twist with Re z β‰  0 has modulus different from one at every ideal of absolute norm greater than one, so such twists live only in the general carrier.

References #

The general carrier of completely multiplicative ideal weights #

A multiplicative ideal weight on a number field K: a completely multiplicative complex-valued function on all integral ideals of π“ž K, packaged as a monoid-with-zero homomorphism Ideal (π“ž K) β†’*β‚€ β„‚, which kills only finitely many height-one primes.

Being a β†’*β‚€ forces the value 0 at the zero ideal βŠ₯ and the value 1 at ⊀; the finiteness condition is what makes the associated Euler product have finitely many bad local factors. This carrier is degree one: its value at a prime power 𝔭 ^ n is forced to be Ο‡ 𝔭 ^ n, so it excludes the ideal MΓΆbius function and any coefficient system whose prime-power values are independent local data.

Instances For
    theorem TauCeti.MultiplicativeIdealWeight.ext {K : Type u_1} [Field K] [NumberField K] {Ο‡ ψ : MultiplicativeIdealWeight K} (h : βˆ€ (I : Ideal (NumberField.RingOfIntegers K)), Ο‡ I = ψ I) :
    Ο‡ = ψ
    theorem TauCeti.MultiplicativeIdealWeight.ext_iff {K : Type u_1} [Field K] [NumberField K] {Ο‡ ψ : MultiplicativeIdealWeight K} :
    Ο‡ = ψ ↔ βˆ€ (I : Ideal (NumberField.RingOfIntegers K)), Ο‡ I = ψ I
    @[simp]

    The zero-ideal law. Every multiplicative ideal weight kills the zero ideal, so no weight is the everywhere-one function on all ideals.

    theorem TauCeti.MultiplicativeIdealWeight.ext_heightOneSpectrum {K : Type u_1} [Field K] [NumberField K] {Ο‡ ψ : MultiplicativeIdealWeight K} (h : βˆ€ (𝔭 : IsDedekindDomain.HeightOneSpectrum (NumberField.RingOfIntegers K)), Ο‡ 𝔭.asIdeal = ψ 𝔭.asIdeal) :
    Ο‡ = ψ

    A multiplicative ideal weight is determined by its values at the height-one primes: every nonzero ideal of π“ž K is a product of them.

    The bad primes of an ideal weight: the height-one primes it kills. This is a derived, canonically determined accessor, not extra data.

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      @[reducible, inline]

      An ideal is good for Ο‡ when it is prime to the bad primes of Ο‡. In particular a good ideal is nonzero, even when Ο‡ has no bad primes at all.

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        A completely multiplicative ideal weight is nonzero exactly on the good ideals. Thus the good ideals are precisely the nonvanishing locus of the weight.

        Constructors and operations #

        The indicator weight of a finite set S of height-one primes: the value is 1 on the ideals prime to S and 0 elsewhere. Its bad primes are exactly S, and ofBadPrimes βˆ… is the trivial weight 1.

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          @[instance_reducible]

          The pointwise product of two multiplicative ideal weights.

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          @[simp]
          theorem TauCeti.MultiplicativeIdealWeight.mul_apply {K : Type u_1} [Field K] [NumberField K] (Ο‡ ψ : MultiplicativeIdealWeight K) (I : Ideal (NumberField.RingOfIntegers K)) :
          (Ο‡ * ψ) I = Ο‡ I * ψ I
          @[instance_reducible]

          The trivial multiplicative ideal weight.

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          @[simp]

          The trivial weight is the indicator of the nonzero ideals.

          @[instance_reducible]

          The pointwise product of multiplicative ideal weights, with the trivial weight as unit. It is not the Dirichlet convolution of ideal arithmetic functions, which is TauCeti.IdealArithmeticFunction.convolution.

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          @[simp]
          theorem TauCeti.MultiplicativeIdealWeight.pow_apply {K : Type u_1} [Field K] [NumberField K] (Ο‡ : MultiplicativeIdealWeight K) {n : β„•} (hn : n β‰  0) (I : Ideal (NumberField.RingOfIntegers K)) :
          (Ο‡ ^ n) I = Ο‡ I ^ n

          A positive power of a weight is computed pointwise. The exponent must be nonzero: Ο‡ ^ 0 is the trivial weight, which vanishes at βŠ₯, while Ο‡ βŠ₯ ^ 0 = 1.

          @[simp]

          A nonzero power of a weight kills exactly the primes the weight kills, so it has the same good ideals.

          Restriction away from a finite set of primes: Ο‡ is left unchanged on the ideals prime to S and set to 0 on the others.

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            @[simp]

            Restricting away from no prime at all changes nothing.

            Forbidding one more prime. Restricting away from insert 𝔭 S kills the ideals divisible by 𝔭 and agrees with the restriction away from S on the others.

            @[simp]

            Restricting the trivial weight away from S gives the indicator weight of ideals prime to every prime in S.

            @[simp]

            Restriction commutes with nonzero powers. The exponent must be nonzero: (Ο‡ ^ 0).restrict S hS is the indicator weight ofBadPrimes S hS, while Ο‡.restrict S hS ^ 0 is the trivial weight.

            The conjugate weight I ↦ conj (Ο‡ I).

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              @[simp]
              theorem TauCeti.MultiplicativeIdealWeight.conj_mul {K : Type u_1} [Field K] [NumberField K] (Ο‡ ψ : MultiplicativeIdealWeight K) :
              (Ο‡ * ψ).conj = Ο‡.conj * ψ.conj

              Conjugation is multiplicative for the pointwise product.

              @[simp]
              theorem TauCeti.MultiplicativeIdealWeight.conj_pow {K : Type u_1} [Field K] [NumberField K] (Ο‡ : MultiplicativeIdealWeight K) (n : β„•) :
              (Ο‡ ^ n).conj = Ο‡.conj ^ n

              Conjugation commutes with powers; in particular the conjugate of the pointwise square is the square of the conjugate.

              The norm twist I ↦ Ο‡ I * N(I) ^ (-z). For general z this leaves the unitary carrier; only the purely imaginary twists preserve it (TauCeti.UnitaryIdealWeight.normTwist).

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                @[simp]

                Successive norm twists combine by adding their parameters.

                @[simp]
                theorem TauCeti.MultiplicativeIdealWeight.normTwist_mul_normTwist {K : Type u_1} [Field K] [NumberField K] (z w : β„‚) (Ο‡ ψ : MultiplicativeIdealWeight K) :
                normTwist z Ο‡ * normTwist w ψ = normTwist (z + w) (Ο‡ * ψ)

                The pointwise product of two norm twists is the twist of the product by the sum of the parameters.

                @[simp]
                theorem TauCeti.MultiplicativeIdealWeight.normTwist_pow {K : Type u_1} [Field K] [NumberField K] (z : β„‚) (Ο‡ : MultiplicativeIdealWeight K) (n : β„•) :
                normTwist z Ο‡ ^ n = normTwist (↑n * z) (Ο‡ ^ n)

                The n-th power of a norm twist is the twist of the n-th power by n times the parameter. For n = 2: the pointwise square of the twist of Ο‡ by N(I) ^ (-z) is the twist of Ο‡ ^ 2 by N(I) ^ (-2z).

                Weights that are norm twists on their good locus #

                A weight is a norm twist on its good ideals, with parameter u, when Ο‡ I = N(I) ^ (u * I) at every ideal I prime to its bad primes. Away from the bad primes such a weight is the purely imaginary norm twist TauCeti.MultiplicativeIdealWeight.normTwist of the trivial weight, and it is the whole of that twist once the bad primes are taken into account (TauCeti.MultiplicativeIdealWeight.IsNormTwistOnGood.eq_normTwist).

                These weights give degenerate examples in families of ideal weights: their L-series is a Dedekind zeta function with finitely many Euler factors deleted, read after an imaginary translation, so it has a pole and no cancellation in its ideal partial sums (TauCeti.not_hasCancellation_of_isNormTwistOnGood).

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                  A weight is trivial on its good ideals when it takes the value 1 at every ideal prime to its bad primes; equivalently it is a norm twist on its good ideals with parameter 0 (TauCeti.MultiplicativeIdealWeight.isNormTwistOnGood_zero_iff).

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                    @[simp]

                    A weight trivial on its good ideals takes the value 1 at each of them.

                    @[simp]

                    The norm twists with parameter 0 on the good ideals are the weights that are trivial there.

                    The trivial weight is trivial on its good ideals, which are all the nonzero ideals.

                    The indicator of the ideals prime to a finite set S of primes is trivial on its good ideals, which are exactly those ideals.

                    A norm twist on the good ideals is a norm twist of an indicator weight. A weight that is a norm twist with parameter u on its good ideals is the twist by N(I) ^ (u * I) of the indicator of the ideals prime to its bad primes. The bad set is a parameter, so that a caller holding it as a Finset need not convert.

                    A twist adds to the parameter. Twisting by N(I) ^ (v * I) turns a norm twist with parameter u on the good ideals into one with parameter u + v; the good ideals are unchanged.

                    Converse of TauCeti.MultiplicativeIdealWeight.IsNormTwistOnGood.eq_normTwist. The twist by N(I) ^ (u * I) of the indicator of the ideals prime to a finite set of primes is a norm twist with parameter u on its good ideals.

                    Conjugation negates the parameter of a norm twist on the good ideals.

                    theorem TauCeti.MultiplicativeIdealWeight.IsNormTwistOnGood.mul {K : Type u_1} [Field K] [NumberField K] {Ο‡ ψ : MultiplicativeIdealWeight K} {u v : ℝ} (hΟ‡ : Ο‡.IsNormTwistOnGood u) (hψ : ψ.IsNormTwistOnGood v) :
                    (Ο‡ * ψ).IsNormTwistOnGood (u + v)

                    The pointwise product adds the parameters of two norm twists on the good ideals. Both factors are good at every ideal good for the product, since the bad primes of a product are the union of those of its factors.

                    The n-th power multiplies the parameter by n for a norm twist on the good ideals. For n = 2 this identifies the pointwise square of such a weight as a norm twist with parameter 2u on its good ideals.

                    Passage to the general carrier, and the zero-ideal rejection test #

                    The ideal arithmetic function underlying an ideal weight: its restriction to the nonzero ideals.

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                      The ideal arithmetic function underlying a norm twist multiplies by N(I) ^ (-z).

                      @[simp]

                      Regrouping absorbs a norm twist. Twisting a weight by N(I) ^ (-z) twists its n-th norm coefficient by n ^ (-z).

                      The ideal arithmetic function underlying a completely multiplicative ideal weight is multiplicative on relatively prime ideals.

                      @[simp]

                      An ideal weight is recovered from its restriction to the nonzero ideals by extending by zero: the zero-ideal law Ο‡ βŠ₯ = 0 is exactly what makes this work.

                      Rejection test. The everywhere-one function on all integral ideals underlies no multiplicative ideal weight, since Ideal (π“ž K) β†’*β‚€ β„‚ forces the value 0 at βŠ₯. The everywhere-one function on the nonzero ideals is the trivial weight (TauCeti.MultiplicativeIdealWeight.toIdealArithmeticFunction_one).

                      Functoriality under an isomorphism of fields #

                      Transport along an isomorphism of fields. An isomorphism e : K ≃+* L carries a multiplicative ideal weight on K to one on L, by pulling ideals of π“ž L back to π“ž K along NumberField.RingOfIntegers.mapRingEquiv e.

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                        @[simp]

                        The bad primes transport too: they are carried along by the induced bijection of height-one spectra.

                        theorem TauCeti.MultiplicativeIdealWeight.map_map {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} {M : Type u_3} [Field L] [NumberField L] [Field M] [NumberField M] (e : K ≃+* L) (e' : L ≃+* M) (Ο‡ : MultiplicativeIdealWeight K) :
                        map e' (map e Ο‡) = map (e.trans e') Ο‡

                        Transport is functorial: transporting along e and then along e' is the same as transporting along e.trans e'.

                        Transport preserves the pointwise CommMonoid structure.

                        @[simp]
                        theorem TauCeti.MultiplicativeIdealWeight.map_one {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) :
                        map e 1 = 1
                        @[simp]
                        theorem TauCeti.MultiplicativeIdealWeight.map_mul {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ ψ : MultiplicativeIdealWeight K) :
                        map e (Ο‡ * ψ) = map e Ο‡ * map e ψ

                        Transport along an isomorphism of fields, as a multiplicative equivalence of the two carriers, with inverse the transport along e.symm.

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                          @[simp]
                          theorem TauCeti.MultiplicativeIdealWeight.mapEquiv_apply {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : MultiplicativeIdealWeight K) :
                          (mapEquiv e) Ο‡ = map e Ο‡
                          @[simp]
                          @[simp]

                          Transport carries an indicator weight to the indicator of the image prime set.

                          @[simp]

                          Transport commutes with restriction after carrying the excluded prime set forward.

                          @[simp]
                          theorem TauCeti.MultiplicativeIdealWeight.map_conj {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : MultiplicativeIdealWeight K) :
                          map e Ο‡.conj = (map e Ο‡).conj

                          Transport commutes with complex conjugation.

                          @[simp]
                          theorem TauCeti.MultiplicativeIdealWeight.map_normTwist {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (z : β„‚) (Ο‡ : MultiplicativeIdealWeight K) :
                          map e (normTwist z Ο‡) = normTwist z (map e Ο‡)

                          Transport commutes with norm twists because absolute ideal norm is invariant under a ring equivalence.

                          The unitary subtype #

                          @[reducible, inline]
                          abbrev TauCeti.UnitaryIdealWeight (K : Type u_2) [Field K] [NumberField K] :
                          Type u_2

                          A unitary ideal weight: a multiplicative ideal weight whose values have modulus 1 away from its bad primes. Finite-order Hecke characters land here (TauCeti.UnitaryIdealWeight.ofPowEqOne), and so do the purely imaginary norm twists (TauCeti.UnitaryIdealWeight.normTwist); a norm twist with Re z β‰  0 does not (TauCeti.UnitaryIdealWeight.norm_normTwist_apply_ne_one).

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                            theorem TauCeti.UnitaryIdealWeight.norm_eq_one {K : Type u_1} [Field K] [NumberField K] (Ο‡ : UnitaryIdealWeight K) {I : Ideal (NumberField.RingOfIntegers K)} (hI : (↑χ).IsGood I) :
                            ‖↑χ Iβ€– = 1

                            A unitary weight has modulus one on every good ideal, extending its defining condition from good primes to the entire good-ideal locus.

                            A unitary weight is bounded by one on every ideal. The bound is unconditional: it carries no goodness hypothesis, so a comparison indexed by all of (Ideal (π“ž K))⁰ can apply it termwise. norm_eq_one is sharper where it applies, but obliges the caller to split that index type first; this is the form a convergence estimate wants.

                            A weight trivial on its good ideals is unitary, so it is bounded by one on every ideal (TauCeti.UnitaryIdealWeight.norm_le_one).

                            @[instance_reducible]
                            noncomputable instance TauCeti.UnitaryIdealWeight.instOne {K : Type u_1} [Field K] [NumberField K] :

                            The trivial weight is unitary.

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                            theorem TauCeti.UnitaryIdealWeight.val_one {K : Type u_1} [Field K] [NumberField K] :
                            ↑1 = 1
                            @[instance_reducible]
                            noncomputable instance TauCeti.UnitaryIdealWeight.instMul {K : Type u_1} [Field K] [NumberField K] :

                            The pointwise product of unitary weights is unitary.

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                            theorem TauCeti.UnitaryIdealWeight.val_mul {K : Type u_1} [Field K] [NumberField K] (Ο‡ ψ : UnitaryIdealWeight K) :
                            ↑(Ο‡ * ψ) = ↑χ * β†‘Οˆ
                            @[instance_reducible]

                            Pointwise multiplication makes the unitary weights a commutative monoid.

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                            @[simp]
                            theorem TauCeti.UnitaryIdealWeight.val_pow {K : Type u_1} [Field K] [NumberField K] (Ο‡ : UnitaryIdealWeight K) (n : β„•) :
                            ↑(Ο‡ ^ n) = ↑χ ^ n
                            def TauCeti.UnitaryIdealWeight.ofPowEqOne {K : Type u_1} [Field K] [NumberField K] (Ο‡ : MultiplicativeIdealWeight K) {n : β„•} (hn : n β‰  0) (h : βˆ€ 𝔭 βˆ‰ Ο‡.badPrimes, Ο‡ 𝔭.asIdeal ^ n = 1) :

                            Finite-order weights are unitary. If a positive power of Ο‡ takes the value 1 at every good prime β€” as for a finite-order Hecke character β€” then Ο‡ is unitary.

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                              @[simp]
                              theorem TauCeti.UnitaryIdealWeight.val_ofPowEqOne {K : Type u_1} [Field K] [NumberField K] (Ο‡ : MultiplicativeIdealWeight K) {n : β„•} (hn : n β‰  0) (h : βˆ€ 𝔭 βˆ‰ Ο‡.badPrimes, Ο‡ 𝔭.asIdeal ^ n = 1) :
                              ↑(ofPowEqOne Ο‡ hn h) = Ο‡
                              noncomputable def TauCeti.UnitaryIdealWeight.normTwist {K : Type u_1} [Field K] [NumberField K] (z : β„‚) (hz : z.re = 0) (Ο‡ : UnitaryIdealWeight K) :

                              Imaginary norm twists preserve unitarity. For Re z = 0 the factor N(I) ^ (-z) has modulus 1, so the twisted weight is again unitary.

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                                @[simp]
                                theorem TauCeti.UnitaryIdealWeight.val_normTwist {K : Type u_1} [Field K] [NumberField K] (z : β„‚) (hz : z.re = 0) (Ο‡ : UnitaryIdealWeight K) :
                                ↑(normTwist z hz Ο‡) = MultiplicativeIdealWeight.normTwist z ↑χ
                                @[simp]

                                The zero norm twist acts trivially on unitary weights.

                                @[simp]
                                theorem TauCeti.UnitaryIdealWeight.normTwist_normTwist {K : Type u_1} [Field K] [NumberField K] (z w : β„‚) (hz : z.re = 0) (hw : w.re = 0) (Ο‡ : UnitaryIdealWeight K) :
                                normTwist z hz (normTwist w hw Ο‡) = normTwist (z + w) β‹― Ο‡

                                Successive imaginary norm twists of a unitary weight combine by adding their parameters.

                                @[simp]
                                theorem TauCeti.UnitaryIdealWeight.normTwist_mul_normTwist {K : Type u_1} [Field K] [NumberField K] (z w : β„‚) (hz : z.re = 0) (hw : w.re = 0) (Ο‡ ψ : UnitaryIdealWeight K) :
                                normTwist z hz Ο‡ * normTwist w hw ψ = normTwist (z + w) β‹― (Ο‡ * ψ)

                                The pointwise product of two imaginary norm twists of unitary weights is the twist of the product by the sum of the parameters.

                                @[simp]
                                theorem TauCeti.UnitaryIdealWeight.normTwist_pow {K : Type u_1} [Field K] [NumberField K] (z : β„‚) (hz : z.re = 0) (Ο‡ : UnitaryIdealWeight K) (n : β„•) :
                                normTwist z hz Ο‡ ^ n = normTwist (↑n * z) β‹― (Ο‡ ^ n)

                                The n-th power of an imaginary norm twist of a unitary weight is the twist of the n-th power by n times the parameter.

                                The modulus of an arbitrary norm twist. At a good ideal, twisting a unitary weight by z gives modulus N(I) ^ (-Re z); only the purely imaginary twists therefore stay unitary.

                                Rejection test. A norm twist with Re z β‰  0 leaves the unitary carrier: at every ideal of absolute norm greater than one its modulus differs from 1, being N(I) ^ (-Re z) at a good ideal and 0 elsewhere. Such twists therefore live only in TauCeti.MultiplicativeIdealWeight.

                                The conjugate of a unitary weight is unitary.

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                                  @[simp]
                                  theorem TauCeti.UnitaryIdealWeight.val_conj {K : Type u_1} [Field K] [NumberField K] (Ο‡ : UnitaryIdealWeight K) :
                                  ↑χ.conj = (↑χ).conj
                                  @[simp]
                                  @[simp]
                                  theorem TauCeti.UnitaryIdealWeight.conj_mul {K : Type u_1} [Field K] [NumberField K] (Ο‡ ψ : UnitaryIdealWeight K) :
                                  (Ο‡ * ψ).conj = Ο‡.conj * ψ.conj

                                  Conjugation of unitary weights is multiplicative for the pointwise product.

                                  @[simp]
                                  theorem TauCeti.UnitaryIdealWeight.conj_pow {K : Type u_1} [Field K] [NumberField K] (Ο‡ : UnitaryIdealWeight K) (n : β„•) :
                                  (Ο‡ ^ n).conj = Ο‡.conj ^ n

                                  Conjugation of unitary weights commutes with powers, in particular with the pointwise square.

                                  Restricting a unitary weight away from a finite set of primes keeps it unitary: the restricted weight is unchanged at the primes that are good for it.

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                                    @[simp]
                                    @[simp]

                                    Restricting a unitary weight away from no prime at all changes nothing.

                                    @[simp]

                                    Restriction of unitary weights commutes with nonzero powers, in particular with the pointwise square. As for TauCeti.MultiplicativeIdealWeight.restrict_pow, the exponent 0 is excluded.

                                    noncomputable def TauCeti.UnitaryIdealWeight.map {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : UnitaryIdealWeight K) :

                                    Transport along an isomorphism of fields preserves unitarity: the transported weight has the same values as Ο‡, read off at the corresponding primes.

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                                      @[simp]
                                      theorem TauCeti.UnitaryIdealWeight.val_map {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : UnitaryIdealWeight K) :
                                      ↑(map e Ο‡) = MultiplicativeIdealWeight.map e ↑χ
                                      @[simp]
                                      theorem TauCeti.UnitaryIdealWeight.map_map {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} {M : Type u_3} [Field L] [NumberField L] [Field M] [NumberField M] (e : K ≃+* L) (e' : L ≃+* M) (Ο‡ : UnitaryIdealWeight K) :
                                      map e' (map e Ο‡) = map (e.trans e') Ο‡

                                      Transport is functorial on the unitary carrier as well.

                                      Transport preserves the pointwise CommMonoid structure of the unitary carrier too.

                                      @[simp]
                                      theorem TauCeti.UnitaryIdealWeight.map_one {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) :
                                      map e 1 = 1
                                      @[simp]
                                      theorem TauCeti.UnitaryIdealWeight.map_mul {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ ψ : UnitaryIdealWeight K) :
                                      map e (Ο‡ * ψ) = map e Ο‡ * map e ψ

                                      Transport along an isomorphism of fields, as a multiplicative equivalence of the unitary carriers.

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                                        @[simp]
                                        theorem TauCeti.UnitaryIdealWeight.mapEquiv_apply {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : UnitaryIdealWeight K) :
                                        (mapEquiv e) Ο‡ = map e Ο‡
                                        @[simp]
                                        theorem TauCeti.UnitaryIdealWeight.mapEquiv_symm_apply {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : UnitaryIdealWeight L) :
                                        (mapEquiv e).symm Ο‡ = map e.symm Ο‡
                                        @[simp]

                                        Transport commutes with restriction on unitary weights after carrying the excluded prime set forward.

                                        @[simp]
                                        theorem TauCeti.UnitaryIdealWeight.map_conj {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (Ο‡ : UnitaryIdealWeight K) :
                                        map e Ο‡.conj = (map e Ο‡).conj

                                        Transport commutes with complex conjugation on unitary weights.

                                        @[simp]
                                        theorem TauCeti.UnitaryIdealWeight.map_normTwist {K : Type u_1} [Field K] [NumberField K] {L : Type u_2} [Field L] [NumberField L] (e : K ≃+* L) (z : β„‚) (hz : z.re = 0) (Ο‡ : UnitaryIdealWeight K) :
                                        map e (normTwist z hz Ο‡) = normTwist z hz (map e Ο‡)

                                        Transport commutes with purely imaginary norm twists on unitary weights.

                                        The ideal arithmetic function underlying a unitary weight: the restriction of the underlying multiplicative weight to the nonzero ideals.

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                                          The ideal arithmetic function of a unitary weight agrees with that of its underlying multiplicative weight.

                                          @[simp]
                                          theorem TauCeti.UnitaryIdealWeight.normCoeff_normTwist {K : Type u_1} [Field K] [NumberField K] (z : β„‚) (hz : z.re = 0) (Ο‡ : UnitaryIdealWeight K) (n : β„•) :

                                          Regrouping absorbs an imaginary norm twist. For z.re = 0, twisting a unitary weight by N(I) ^ (-z) multiplies its n-th norm coefficient by n ^ (-z).

                                          The ideal arithmetic function underlying a unitary ideal weight is multiplicative on relatively prime ideals.

                                          @[simp]

                                          A unitary weight is recovered from its underlying ideal arithmetic function by extending by zero, just as in TauCeti.MultiplicativeIdealWeight.zeroExtend_toIdealArithmeticFunction.

                                          @[simp]

                                          The trivial unitary weight restricts to the constant-one ideal arithmetic function.

                                          A unitary weight is determined by its ideal arithmetic function.