Chen 1973, Lemma 5: the actual switched triple source #
This file freezes the opening of Lemma 5 on pp. 116--119 of Chen's original
scan. It keeps the actual von Mangoldt coefficient, Chen's finite Perron kernel
Φ(x/(p₁p₂n)), and the reciprocal logarithmic weight. In particular it does
not replace the source by an arbitrary coefficient sequence.
The analytic estimates in Lemmas 5--6 are not asserted here. The first layer is
the exact finite bookkeeping used before those estimates: the prime-triple
carrier, the Selberg-square expansion, the principal/nonprincipal partition,
and the resulting M₁-M₃+M₄ identity.
A natural cutoff version of Chen's Q=∏_{2≤p<x^(1/4)}p.
The relation to the real fourth root is carried separately, so the finite
product never uses a fake real-indexed finset.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5Q z4 = ∏ p ∈ Finset.range z4 with 2 ≤ p ∧ Nat.Prime p, p
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An honest natural cutoff realizes the source's strict real fourth-root cutoff when these membership predicates agree.
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Under the explicit cutoff bridge, membership in the finite Q carrier is
exactly the source condition 2 ≤ p < x^(1/4).
The finite pair carrier printed at the start of Lemma 5:
x^(1/10)<p₁≤x^(1/3)<p₂≤(x/p₁)^(1/2).
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The actual finite triple carrier counted by Ω, before the coprimality
sieve is imposed.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimeTriples x = {t ∈ (AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x).product (Finset.range (x + 1)) | Nat.Prime t.2 ∧ t.2 ≤ x / (t.1.1 * t.1.2)}
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Chen's Ω: prime triples in the printed carrier for which
(x-p₁p₂p₃,Q)=1.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5OmegaCarrier x z4 = {t ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimeTriples x | (x - t.1.1 * t.1.2 * t.2).Coprime (AnalyticNumberTheory.LargeSieve.chen1973Lemma5Q z4)}
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The integer counted by the source symbol Ω.
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Chen p. 115: f(k)=φ(k)∏_{p∣k}(p-2)/(p-1).
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergF k = ↑k.totient * ∏ p ∈ k.primeFactors, (↑p - 2) / (↑p - 1)
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The normalized finite denominator in Chen's literal Selberg coefficient.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergDenominator x R = ∑ k ∈ Finset.range (R + 1) with 1 ≤ k ∧ k.Coprime x, ↑(ArithmeticFunction.moebius k) ^ 2 / AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergF k
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The actual coefficient λ_d defined immediately before Lemma 5 (p. 115).
R is the honest natural version of x^(1/4-ε/2).
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergLambda x R d = if d = 1 then 1 else if R < d then 0 else (↑(ArithmeticFunction.moebius d) / (AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergF d * (↑d.totient)⁻¹) * ∑ k ∈ Finset.range (R / d + 1) with 1 ≤ k ∧ k.Coprime (x * d), ↑(ArithmeticFunction.moebius k) ^ 2 / AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergF k) * (AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergDenominator x R)⁻¹
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The finite n≤x/(p₁p₂) carrier used after switching p₃ to Λ(n).
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp = {n ∈ Finset.range (x + 1) | n ≤ x / (pp.1 * pp.2)}
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The literal source weight
Λ(n) Φ(x/(p₁p₂n)) / log(x/(p₁p₂)).
The value at a zero denominator is totalized by Lean's field operations; on the
prime-pair carrier the later analytic development proves the required
positivity separately.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n = ArithmeticFunction.vonMangoldt n * AnalyticNumberTheory.LargeSieve.chen1973PerronKernelFinite (↑x) (↑x / (↑pp.1 * ↑pp.2 * ↑n)) / Real.log (↑x / (↑pp.1 * ↑pp.2))
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The unsmoothed switched main sum M printed on p. 116.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M x z4 = ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x, 1 / Real.log (↑x / (↑pp.1 * ↑pp.2)) * ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, if (x - pp.1 * pp.2 * n).Coprime (AnalyticNumberTheory.LargeSieve.chen1973Lemma5Q z4) then ArithmeticFunction.vonMangoldt n else 0
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The divisor support in the Selberg square: d∣Q, (d,x)=1.
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The finite Selberg divisor sum appearing inside the square in (5).
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorSum x z4 lambda pp n = ∑ d ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, if d ∣ x - pp.1 * pp.2 * n then lambda d else 0
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The exact smoothed Selberg square before expanding in d₁,d₂.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5SelbergSquare x z4 lambda = ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x, ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n * AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorSum x z4 lambda pp n ^ 2
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The literal switched Λ·Φ/log mass on the Ω carrier. Keeping this
quantity separate avoids silently replacing Chen's smoothed source by a bare
cardinality.
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The source weight is nonnegative once its (printed) logarithmic denominator
is known to be nonnegative. The nonnegativity of Λ and of Chen's finite
Perron kernel are discharged internally.
The finite product defining Q is nonzero.
On an Ω residue, every divisor of Q which divides the residue is one;
therefore a Selberg divisor sum normalized by λ₁=1 is exactly one.
Exact reindexing of the smoothed Ω source into the switched pair/n
coordinates used by the Selberg square.
The actual smoothed Ω mass is bounded by the actual Selberg square. The
only hypotheses are λ₁=1 and nonnegativity of the source weights; the latter
is supplied by chen1973Lemma5SmoothedWeight_nonneg from the genuine
Λ·Φ/log definition.
A separate, honest cardinal bridge. It applies when the retained smoothed weight is pointwise at least one; this condition is deliberately explicit and is not conflated with mere nonnegativity of the Perron weight.
Cardinal form of the Ω--Selberg-square bridge, with the genuinely stronger
pointwise lower bound isolated from the internally proved sign condition.
The progression sum denoted N_[d₁,d₂] in (5).
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5ProgressionTerm x d1 d2 = ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x, ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, if d1.lcm d2 ∣ x - pp.1 * pp.2 * n then AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n else 0
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Expansion of Chen's Selberg square into the two divisor variables.
Principal-character sum with no coprimality deletion.
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The part of the principal sum satisfying (p₁p₂n,d₁d₂)=1.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrincipalGood x d1 d2 = (↑(d1.lcm d2).totient)⁻¹ * ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x, ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, if (pp.1 * pp.2 * n).Coprime (d1 * d2) then AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n else 0
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The complementary principal contribution (p₁p₂n,d₁d₂)>1, source M₃.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrincipalBad x d1 d2 = (↑(d1.lcm d2).totient)⁻¹ * ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x, ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, if (pp.1 * pp.2 * n).Coprime (d1 * d2) then 0 else AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n
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Pure finite partition of the principal sum into good and bad gcd lanes.
Source M₁: the unrestricted principal-character main term.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M1 x z4 lambda = ∑ d1 ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, ∑ d2 ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, lambda d1 * lambda d2 * AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrincipalAll x d1 d2
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Source M₃: the non-coprime correction removed from M₁.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M3 x z4 lambda = ∑ d1 ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, ∑ d2 ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, lambda d1 * lambda d2 * AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrincipalBad x d1 d2
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Source M₄ at the finite pre-contour level: the exact progression
remainder after subtracting the coprime principal-character term.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M4 x z4 lambda = ∑ d1 ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, ∑ d2 ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5DivisorCarrier x z4, lambda d1 * lambda d2 * (AnalyticNumberTheory.LargeSieve.chen1973Lemma5ProgressionTerm x d1 d2 - AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrincipalGood x d1 d2)
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The actual twisted switched source at modulus q; the coefficient remains
literally Λ(n) Φ(x/(p₁p₂n)) / log(x/(p₁p₂)).
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimitiveTwist x q χ = star (↑χ ↑x) * ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x, ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, ↑(AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n) * ↑χ ↑(pp.1 * pp.2 * n)
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The pointwise Dirichlet-character orthogonality relation needed to turn a progression condition into a character sum. Unlike a black-box source premise, this finite step is proved directly from Mathlib's orthogonality API.
The old one-conductor signed ledger. It is useful as the inner
character majorant, but it is not Chen's p. 117--119 source M₂: that source
still has an outer squarefree d-sum and the restriction (p₁p₂,d)=1.
Equations
- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2Signed x D = ∑ l ∈ Finset.range (D + 1) with l.Coprime x ∧ Squarefree l, ↑(ArithmeticFunction.moebius l) ^ 2 * 3 ^ l.primeFactors.card / ↑l.totient * (∑ χ : AnalyticNumberTheory.LargeSieve.PrimitiveCharacter l, if ↑χ = 1 then 0 else AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimitiveTwist x l χ).re
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Compatibility name for the old one-conductor norm ledger. This is only an
inner majorant (the shape later denoted N_m after inserting a prime-pair
filter), not the source M₂ of Lemma 5. The source-faithful object is
chen1973Lemma5M2Source below.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2InnerMajorant x D = ∑ l ∈ Finset.range (D + 1) with l.Coprime x ∧ Squarefree l, ↑(ArithmeticFunction.moebius l) ^ 2 * 3 ^ l.primeFactors.card / ↑l.totient * ‖∑ χ : AnalyticNumberTheory.LargeSieve.PrimitiveCharacter l, if ↑χ = 1 then 0 else AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimitiveTwist x l χ‖
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Legacy API retained for downstream files. Semantically this is the
one-conductor inner majorant, not source M₂.
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The p. 119 outer squarefree-divisor carrier.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2OuterDivisors x D = {d ∈ Finset.Icc 2 D | d.Coprime x ∧ Squarefree d}
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The p. 119 outer weight 3^ν(d)|μ(d)|/φ(d).
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The literal primitive twist after retaining the source condition
(p₁p₂,d)=1. The character conductor is the independent inner variable l.
Equations
- AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimitiveTwistCoprime x l d χ = star (↑χ ↑x) * ∑ pp ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimePairs x with (pp.1 * pp.2).Coprime d, ∑ n ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5NCarrier x pp, ↑(AnalyticNumberTheory.LargeSieve.chen1973Lemma5SmoothedWeight x pp n) * ↑χ ↑(pp.1 * pp.2 * n)
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The inner conductor sum at a fixed outer divisor d.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2SourceInner x D d = ∑ l ∈ Finset.range (D + 1) with l.Coprime x ∧ Squarefree l, ↑(ArithmeticFunction.moebius l) ^ 2 * 3 ^ l.primeFactors.card / ↑l.totient * ‖∑ χ : AnalyticNumberTheory.LargeSieve.PrimitiveCharacter l, if ↑χ = 1 then 0 else AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimitiveTwistCoprime x l d χ‖
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Source-faithful M₂ on pp. 117--119: first the outer d weight, then the
independent inner conductor l primitive-character sum, with
(p₁p₂,d)=1 inside the prime-pair carrier.
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Signed pre-norm form of the same two-layer source. This is the exact finite
target for the Selberg/character expansion of the actual M₄ remainder.
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- AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2SourceSigned x D = ∑ d ∈ AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2OuterDivisors x D, AnalyticNumberTheory.LargeSieve.chen1973Lemma5M2OuterWeight d * ∑ l ∈ Finset.range (D + 1) with l.Coprime x ∧ Squarefree l, ↑(ArithmeticFunction.moebius l) ^ 2 * 3 ^ l.primeFactors.card / ↑l.totient * (∑ χ : AnalyticNumberTheory.LargeSieve.PrimitiveCharacter l, if ↑χ = 1 then 0 else AnalyticNumberTheory.LargeSieve.chen1973Lemma5PrimitiveTwistCoprime x l d χ).re
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The old one-conductor real-part ledger is bounded by its norm ledger.
Taking norms conductor-by-conductor bounds the signed two-layer source.
Finite M₄ ≤ M₂ connector with the correct source object. The premise is
exactly the still-separate Selberg-coefficient/imprimitive-character expansion;
the norm step itself is proved here.
The preceding connector specialized to Chen's actual p. 115 Selberg
coefficient, making the link to the concrete M₄ remainder explicit.
Exact finite M₁-M₃+M₄ decomposition of the expanded Selberg square.
Equation (5), now as a kernel-checked finite identity.
Equation (5) specialized to Chen's actual p. 115 Selberg coefficient.