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Prime Dilation and Alternating Cubes for the Binary Totient Series

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This page uses the notation of the binary totient sketch: S=∑n≥1φ(n)2−nS=\sum_{n\ge1}\varphi(n)2^{-n} and TN=∑h≥1φ(N+h)2−hT_N=\sum_{h\ge1}\varphi(N+h)2^{-h}, so TN=2NS−ΦNT_N=2^NS-\Phi_N with ΦN∈Z\Phi_N\in\mathbb Z. If S=a/qS=a/q with integers a,q≥1a,q\ge1, then qTN∈ZqT_N\in\mathbb Z for every N≥0N\ge0. The arguments below are Plasma AI's, author-recorded, and have not received independent review.

The mechanism tested here is the reduction by which Tao and Teräväinen prove that ∑nω(n)2−n\sum_n\omega(n)2^{-n} is irrational, [[../library/arithmetic_functions/tao_2025_quantitative_correlations_problems_prime_factors_consecutive/_index|Section 5 of their correlation paper]] (arXiv:2512.01739v2), the result recorded for Problem 69. Their argument has three moves: a prime dilation of the shift tail, using ω(pm)=ω(m)+1−1p∣m\omega(pm)=\omega(m)+1-1_{p\mid m} (their (5.1)--(5.3)); an alternating sum over a cube of primes that cancels the first KK shifts identically (their (5.4)--(5.8)); and a variance argument that writes the remaining phase as a sum of small, nearly independent prime contributions (their (5.12)--(5.21), with their Theorem 3.1 for the very large primes). Only the shift bookkeeping of the second move is reused below, and it is elementary; no theorem of the source is consumed. The totient analogues of the first two moves are exact. A common-divisor normalization improves their coefficients, but the third move still needs an unproved phase estimate. The results below delimit specific attempted constructions; they do not exclude other decompositions or resolve Problem 249. Here log⁡2\log_2 means logarithm to base two and ln⁡\ln means natural logarithm; the source instead uses log⁡j\log_j for iterated natural logarithms.

The dilation identity

Lemma 1. For a prime pp and an integer N≥0N\ge0,

∑h≥1φ(pN+ph)2h=(p−1) TN+δp(N),δp(N)=∑h≥1, p∣N+hφ(N+h)2h.\sum_{h\ge1}\frac{\varphi(pN+ph)}{2^h}=(p-1)\,T_N+\delta_p(N), \qquad \delta_p(N)=\sum_{h\ge1,\ p\mid N+h}\frac{\varphi(N+h)}{2^h}.

If S=a/qS=a/q, then $q\sum_{h\ge1}\varphi(pN+ph)2^{-h}\equiv q,\delta_p(N) \pmod 1$.

Proof. For every m≥1m\ge1, φ(pm)=(p−1)φ(m)\varphi(pm)=(p-1)\varphi(m) when p∤mp\nmid m and φ(pm)=pφ(m)\varphi(pm)=p\varphi(m) when p∣mp\mid m; that is, φ(pm)=(p−1)φ(m)+φ(m)1p∣m\varphi(pm)=(p-1)\varphi(m)+\varphi(m)1_{p\mid m}. Apply this to m=N+hm=N+h and sum with weights 2−h2^{-h}; both series converge absolutely. The congruence follows from q(p−1)TN∈Zq(p-1)T_N\in\mathbb Z. □\square

The error is weighted by a totient value, unlike the source's indicator error. Two bounds make the difference quantitative. First, for m≥1m\ge1,

φ(m)m=∏ℓ∣m(1−1ℓ)≥∏i=1ω(m)(1−1i+1)=1ω(m)+1≥11+log⁡2m,\frac{\varphi(m)}{m}=\prod_{\ell\mid m}\Bigl(1-\frac1\ell\Bigr) \ge\prod_{i=1}^{\omega(m)}\Bigl(1-\frac1{i+1}\Bigr) =\frac1{\omega(m)+1}\ge\frac1{1+\log_2m},

since the ii-th prime divisor of mm is at least i+1i+1 and 2ω(m)≤m2^{\omega(m)}\le m. Second, the least h0≥1h_0\ge1 with p∣N+h0p\mid N+h_0 satisfies h0≤ph_0\le p, so

δp(N) ≥ φ(N+h0)2h0 ≥ N+12p (1+log⁡2(N+p)).\delta_p(N)\ \ge\ \frac{\varphi(N+h_0)}{2^{h_0}} \ \ge\ \frac{N+1}{2^{p}\,(1+\log_2(N+p))}.

Hence q δp(N)<1/4q\,\delta_p(N)<1/4 forces 2p>4q(N+1)/(1+log⁡2(N+p))2^{p}>4q(N+1)/(1+\log_2(N+p)); for p≤Np\le N this means p≥log⁡2N−log⁡2log⁡2N+log⁡2q+O(1)p\ge\log_2N-\log_2\log_2N+\log_2q+O(1). When p∣Np\mid N (the case p2∣pNp^2\mid pN), the terms are h=kph=kp and δp(N)=∑k≥1φ(N+kp)2−kp≤2(N+2p)2−p\delta_p(N)=\sum_{k\ge1}\varphi(N+kp)2^{-kp}\le2(N+2p)2^{-p}, so this threshold has the right order. For ω\omega the source's error δp\delta_p in (5.3) is at most 21−p2^{1-p} in the corresponding case. When p∤Np\nmid N the error contains the term h0h_0, which can be as large as φ(N+1)/2\varphi(N+1)/2; the source's averaged treatment of that event is discussed under the parameter ranges below.

The alternating cube

Proposition 2. Let K≥1K\ge1 and let p0,v1,…,vKp_0,v_1,\ldots,v_K be integers such that pϵ=p0+∑kϵkvkp_\epsilon=p_0+\sum_k\epsilon_kv_k are distinct primes for all ϵ∈{0,1}K\epsilon\in\{0,1\}^K. Put sϵ=∑k=1Kkϵkvks_\epsilon=\sum_{k=1}^Kk\epsilon_kv_k and rϵ,h=pϵh−sϵr_{\epsilon,h}=p_\epsilon h-s_\epsilon. Let n>∑kk∣vk∣n>\sum_kk|v_k| satisfy n≡sϵ(modpϵ)n\equiv s_\epsilon\pmod{p_\epsilon} for every ϵ\epsilon, and put Nϵ=(n−sϵ)/pϵN_\epsilon=(n-s_\epsilon)/p_\epsilon and

Δh(n)=∑ϵ∈{0,1}K(−1)∣ϵ∣φ(n+rϵ,h).\Delta_h(n)=\sum_{\epsilon\in\{0,1\}^K}(-1)^{|\epsilon|} \varphi(n+r_{\epsilon,h}).

Then Δh(n)=0\Delta_h(n)=0 for 1≤h≤K1\le h\le K, and

∑h>KΔh(n)2h=∑ϵ(−1)∣ϵ∣((pϵ−1)TNϵ+δpϵ(Nϵ)).\sum_{h>K}\frac{\Delta_h(n)}{2^h} =\sum_{\epsilon}(-1)^{|\epsilon|} \bigl((p_\epsilon-1)T_{N_\epsilon}+\delta_{p_\epsilon}(N_\epsilon)\bigr).

If S=a/qS=a/q, then $q\sum_{h>K}\Delta_h(n)2^{-h}\equiv q\sum_\epsilon(-1)^{|\epsilon|}\delta_{p_\epsilon}(N_\epsilon)\pmod1$.

Proof. Since n+rϵ,h=pϵ(Nϵ+h)n+r_{\epsilon,h}=p_\epsilon(N_\epsilon+h), Lemma 1 at (pϵ,Nϵ)(p_\epsilon,N_\epsilon), multiplied by (−1)∣ϵ∣(-1)^{|\epsilon|} and summed, gives the displayed identity once the terms h≤Kh\le K are removed. For h≤Kh\le K, rϵ,h=p0h+∑k(h−k)ϵkvkr_{\epsilon,h}=p_0h+\sum_k(h-k)\epsilon_kv_k does not involve ϵh\epsilon_h; pairing ϵ\epsilon with the vector that differs from it only in coordinate hh gives equal arguments and opposite signs, so Δh(n)=0\Delta_h(n)=0. The congruence follows from q(pϵ−1)TNϵ∈Zq(p_\epsilon-1)T_{N_\epsilon}\in\mathbb Z. □\square

The cancellation for h≤Kh\le K holds for every function in place of φ\varphi; only the right-hand side uses multiplicativity. The congruences are the source's single-power conditions (5.5). Requiring pϵ2∣n−sϵp_\epsilon^2\mid n-s_\epsilon instead means pϵ∣Nϵp_\epsilon\mid N_\epsilon, the case of the pointwise upper bound after Lemma 1.

The identity is exact, and its phase is also a function of the target. Since TN≡{2NS}(mod1)T_N\equiv\{2^NS\}\pmod1, the left side is congruent modulo one to $\sum_\epsilon(-1)^{|\epsilon|}\bigl((p_\epsilon-1){2^{N_\epsilon}S} +\delta_{p_\epsilon}(N_\epsilon)\bigr)$, unconditionally. An estimate for its phase is therefore equally a statement about the binary digits of SS at the 2K2^K positions Nϵ≈n/pϵN_\epsilon\approx n/p_\epsilon. This is the cube counterpart of the one-window reformulation in the sketch.

A common-divisor normalization

Let GG be any positive common divisor of the pϵ−1p_\epsilon-1. Dividing Proposition 2 by GG is compatible with rationality, since every (pϵ−1)/G(p_\epsilon-1)/G is an integer. Thus S=a/qS=a/q implies

qG∑h>KΔh(n)2h≡qG∑ϵ(−1)∣ϵ∣δpϵ(Nϵ)(mod1).(1)\frac qG\sum_{h>K}\frac{\Delta_h(n)}{2^h} \equiv\frac qG\sum_\epsilon(-1)^{|\epsilon|} \delta_{p_\epsilon}(N_\epsilon)\pmod1. \tag{1}

Also φ(pϵm)/G\varphi(p_\epsilon m)/G is an integer for every m≥1m\ge1. Indeed, writing m=pϵaum=p_\epsilon^a u with pϵ∤up_\epsilon\nmid u gives φ(pϵm)=pϵa(pϵ−1)φ(u)\varphi(p_\epsilon m)=p_\epsilon^a(p_\epsilon-1)\varphi(u).

Proposition 2a (weights for the prescribed cube pairings). Suppose nonzero rational weights cϵc_\epsilon are required to cancel separately at each of the paired equal arguments used in Proposition 2, for every 1≤h≤K1\le h\le K. Then cϵ=C(−1)∣ϵ∣c_\epsilon=C(-1)^{|\epsilon|} for one rational CC. The corresponding coefficients cϵ(pϵ−1)c_\epsilon(p_\epsilon-1) on TNϵT_{N_\epsilon} are integers exactly when

Cgcd⁡ϵ(pϵ−1)∈Z.C\gcd_\epsilon(p_\epsilon-1)\in\mathbb Z.

Proof. Each prescribed pairing requires cϵ+cϵ△{h}=0c_\epsilon+c_{\epsilon\mathbin\triangle\{h\}}=0. Connecting vertices by coordinate flips gives the asserted weights. If all C(pϵ−1)C(p_\epsilon-1) are integers, a Bezout combination of the pϵ−1p_\epsilon-1 shows that their gcd times CC is integral. The converse follows because that gcd divides each pϵ−1p_\epsilon-1. □\square

Consequently G=gcd⁡ϵ(pϵ−1)G=\gcd_\epsilon(p_\epsilon-1) gives the largest common normalization within this class of integer tail coefficients. For example, p0=13p_0=13, (v1,v2)=(6,18)(v_1,v_2)=(6,18) gives the prime vertices 13,19,31,3713,19,31,37 and G=6G=6. The normalized tail weights, in that order, are 2,−3,−5,62,-3,-5,6. This saves a factor six. It does not rule out other pairings, cancellations between different levels, or using extra divisibility of the tail integers. For instance qTNqT_N is always even for N≥3N\ge3 under rationality, giving a further fixed factor two.

An averaged estimate and its parameter cost

Put M=2KM=2^K and R=∑kk∣vk∣R=\sum_k k|v_k|. Suppose pϵ∈[P/2,P]p_\epsilon\in[P/2,P], x/2>Rx/2>R, and QQ is divisible by every pϵp_\epsilon but by none of their squares. Let A\mathcal A be the nonempty set of integers in [x/2,x][x/2,x] in a single class modulo QQ satisfying Proposition 2, and put A=∣A∣A=|\mathcal A| and Y=2(x+R)/PY=2(x+R)/P. Expectations below are uniform on A\mathcal A, and e(t)=exp⁡(2πit)e(t)=\exp(2\pi i t).

Proposition 2b (complete error bound). For integers L≥1L\ge1 and H≥KH\ge K, define

ΨG,H(n)=qG∑K<h≤HΔh(n)2h.\Psi_{G,H}(n)=\frac qG\sum_{K<h\le H}\frac{\Delta_h(n)}{2^h}.

If S=a/qS=a/q, then

∣Ee(ΨG,H(n))−1∣≤2ML(2P+1A)+2πqMG((Y+L+2)2−L+(x+R+P(H+2))2−H).(2)\begin{aligned} \bigl|\mathbf E e(\Psi_{G,H}(\mathbf n))-1\bigr| \le{}&2ML\left(\frac2P+\frac1A\right)\\ &+\frac{2\pi qM}{G} \left((Y+L+2)2^{-L} +(x+R+P(H+2))2^{-H}\right). \end{aligned} \tag{2}

Proof. Write the members of A\mathcal A as n0+tQn_0+tQ for AA consecutive integers tt. Then Nϵ=(n0−sϵ)/pϵ+tQ/pϵN_\epsilon=(n_0-s_\epsilon)/p_\epsilon+tQ/p_\epsilon runs through all residues modulo pϵp_\epsilon in a cycle, since pϵ2∤Qp_\epsilon^2\nmid Q. For each hh, the event pϵ∣Nϵ+hp_\epsilon\mid N_\epsilon+h has probability at most 1/pϵ+1/A1/p_\epsilon+1/A. The union of these events for all vertices and 1≤h≤L1\le h\le L has probability at most ML(2/P+1/A)ML(2/P+1/A).

Off this exceptional event, the complete positive error satisfies

δpϵ(Nϵ)≤∑h>L(Nϵ+h)2−h=(Nϵ+L+2)2−L≤(Y+L+2)2−L.\delta_{p_\epsilon}(N_\epsilon) \le\sum_{h>L}(N_\epsilon+h)2^{-h} =(N_\epsilon+L+2)2^{-L}\le(Y+L+2)2^{-L}.

The complete signed tail beyond HH, divided by GG and multiplied by qq, is bounded absolutely by

qMG∑h>H(x+R+Ph)2−h=qMG(x+R+P(H+2))2−H.(3)\frac{qM}{G}\sum_{h>H}(x+R+Ph)2^{-h} =\frac{qM}{G}(x+R+P(H+2))2^{-H}. \tag{3}

Use (1), ∣e(t)−1∣≤2π∣t∣|e(t)-1|\le2\pi|t| off the exceptional event, and the bound two for the difference of two unit complex numbers on that event. This gives (2). No infinite tail has been dropped. □\square

One sufficient asymptotic regime, with qq and 0<η<10<\eta<1 fixed, is

Q≤x1−η,PMln⁡x⟶∞,(4)Q\le x^{1-\eta},\qquad \frac{P}{M\ln x}\longrightarrow\infty, \tag{4}

with integer C→∞C\to\infty, C=o(ln⁡x)C=o(\ln x), and

L=⌈log⁡2qMxPG⌉+C,H=⌈log⁡2qMxG⌉+C.(5)L=\left\lceil\log_2\frac{qMx}{PG}\right\rceil+C, \qquad H=\left\lceil\log_2\frac{qMx}{G}\right\rceil+C. \tag{5}

Here Q≥(P/2)MQ\ge(P/2)^M, M≥2M\ge2, and G<PG<P. Thus P≤2x(1−η)/MP\le2x^{(1-\eta)/M} and x/(PG)≥xη/4x/(PG)\ge x^\eta/4; both cutoffs are positive and of order ln⁡x\ln x. The range of the cube's vertices is ∑k∣vk∣≤P/2\sum_k|v_k|\le P/2, so R≤KP/2R\le KP/2. Also A≥x/(2Q)−1A\ge x/(2Q)-1, M=O(ln⁡x)M=O(\ln x), and Pln⁡x=o(x)P\ln x=o(x). Substitution into (2) makes its right side o(1)o(1). Cubes satisfying these hypotheses are required inputs; no existence claim for arbitrary growing KK is implicit in this estimate.

The regime is nonempty already with K=1K=1. Take two distinct odd primes in [P/2,P][P/2,P], put Q=p0p1Q=p_0p_1, and set x=PDx=P^D for a fixed D>2/(1−η)D>2/(1-\eta). Such pairs exist for all sufficiently large PP by the prime number theorem. The two congruences determine a class modulo QQ, and (4) holds. This supplies an unbounded family for the error estimate, but no saving for its exponential average.

The normalization does not turn this absolute-bound method into a short window argument. Specifically,

log⁡2(x/G)≥(1−1−ηM)log⁡2x−1≥1+η2log⁡2x−1.(6)\log_2(x/G) \ge\left(1-\frac{1-\eta}{M}\right)\log_2x-1 \ge\frac{1+\eta}{2}\log_2x-1. \tag{6}

The right side of (3) cannot tend to zero unless H−log⁡2(qMx/G)→∞H-\log_2(qMx/G)\to\infty. This is a necessity for making that particular upper bound vanish, not a lower bound for the signed tail itself. Selected representatives with Q>x1−ηQ>x^{1-\eta} and estimates using signed cancellation are outside (6). From (4) and Mln⁡(P/2)≤(1−η)ln⁡xM\ln(P/2)\le(1-\eta)\ln x one also obtains

K≤log⁡2ln⁡x−log⁡2ln⁡ln⁡x+O(1).(7)K\le\log_2\ln x-\log_2\ln\ln x+O(1). \tag{7}

The condition P/(Mln⁡x)→∞P/(M\ln x)\to\infty likewise belongs to the exceptional-event bound in (2); it is not necessary for every use of (1). The source's choice P=exp⁡((ln⁡ln⁡ln⁡x)3)P=\exp((\ln\ln\ln x)^3) does not meet it.

The remaining sufficient estimate is now exact: construct admissible parameters with ∣Ee(ΨG,H(n))∣≤1−c|\mathbf E e(\Psi_{G,H}(\mathbf n))|\le1-c for some fixed c>0c>0 along an unbounded sequence. Equations (2)--(5) would contradict S=a/qS=a/q. Doing this for a set of qq containing a multiple of every positive integer would prove irrationality. No such saving is proved.

Where the variance step fails

The source obtains that estimate for ω\omega from the identity ω(m)=∑p1p∣m\omega(m)=\sum_p1_{p\mid m}, which writes its phase as ∑pXp\sum_p\mathbf X_p with each prime piece Xp=o(1)\mathbf X_p=o(1) on its core set (its (5.13) and (5.19)). For φ\varphi the phase has a different shape.

Proposition 3. Let q≥1q\ge1 and η>0\eta>0.

  1. If qq is odd, then for every integer h≥(2+η)ln⁡ln⁡xh\ge(2+\eta)\ln\ln x the number qφ(m)2−hq\varphi(m)2^{-h} is not an integer for all but Oη(x/ln⁡ln⁡x)O_\eta(x/\ln\ln x) integers m≤xm\le x.
  2. For every integer h≤(2−η)ln⁡ln⁡xh\le(2-\eta)\ln\ln x the number qφ(m)2−hq\varphi(m)2^{-h} is an integer for all but Oη(x/ln⁡ln⁡x)O_\eta(x/\ln\ln x) integers m≤xm\le x.

Proof. The valuation is v2(φ(m))=max⁡(a−1,0)+∑ℓ∣m, ℓ oddv2(ℓ−1)v_2(\varphi(m))=\max(a-1,0)+\sum_{\ell\mid m,\ \ell\ \mathrm{odd}}v_2(\ell-1) for 2a∥m2^a\Vert m. The additive function g(m)=∑ℓ∣m, ℓ oddv2(ℓ−1)g(m)=\sum_{\ell\mid m,\ \ell\ \mathrm{odd}}v_2(\ell-1), the sums here running over odd primes ℓ\ell, has mean A(x)=∑ℓ≤xv2(ℓ−1)/ℓ=(2+o(1))ln⁡ln⁡xA(x)=\sum_{\ell\le x}v_2(\ell-1)/\ell=(2+o(1))\ln\ln x. This uses Mertens' theorem in the classes 1 mod 2j1\bmod2^j for each fixed jj, and for the remaining classes the bound ∑ℓ≤x, ℓ≡1 (2j)1/ℓ≪2−j(j+ln⁡ln⁡x)\sum_{\ell\le x,\ \ell\equiv1\ (2^j)}1/\ell\ll2^{-j}(j+\ln\ln x), which follows from the trivial count below 22j2^{2j} and the Brun--Titchmarsh inequality above it. The variance bound is B(x)2=∑ℓ≤xv2(ℓ−1)2/ℓ=O(ln⁡ln⁡x)B(x)^2=\sum_{\ell\le x}v_2(\ell-1)^2/\ell=O(\ln\ln x), by the same bound. In the prime-power form of Turán--Kubilius the mean and squared variance parameter differ from these prime sums by O(1)O(1), since v2(ℓ−1)≤log⁡2ℓv_2(\ell-1)\le\log_2\ell and ∑ℓ(log⁡ℓ)2/ℓ2<∞\sum_{\ell}(\log\ell)^2/\ell^2<\infty. The inequality gives #{m≤x:∣g(m)−A(x)∣>λB(x)}≪x/λ2\#\{m\le x:|g(m)-A(x)|>\lambda B(x)\}\ll x/\lambda^2. The contribution max⁡(a−1,0)\max(a-1,0) exceeds tt for at most x2−tx2^{-t} integers. Taking λ≍ηln⁡ln⁡x\lambda\asymp\eta\sqrt{\ln\ln x} proves both parts; when qq is odd a term is an integer exactly when 2h∣φ(m)2^h\mid\varphi(m). □\square

The all-integers estimate does not give an upper valuation bound on the averaging class. For example, a forced prime divisor congruent to one modulo a large power of two makes every corresponding totient divisible by that power. In particular Proposition 3(1) cannot show that the cube's remaining terms are non-integral, let alone bounded away from integers.

The lower valuation statement does transfer, including after the normalization by GG, by a direct argument. Suppose in addition to (4) that every prime factor of QQ other than the pϵp_\epsilon is at most ww, where ln⁡ln⁡(w+3)=o(ln⁡ln⁡x)\ln\ln(w+3)=o(\ln\ln x). For each vertex and each level h≤Hh\le H separately, and each fixed 0<ε<10<\varepsilon<1, all but a proportion Oε(1/ln⁡ln⁡x)O_\varepsilon(1/\ln\ln x) of the class satisfy

v2(φ(pϵ(Nϵ+h))G)≥(2−ε)ln⁡ln⁡x.(8)v_2\left(\frac{\varphi(p_\epsilon(N_\epsilon+h))}{G}\right) \ge(2-\varepsilon)\ln\ln x. \tag{8}

Here is a proof with its uniformity explicit. Choose a fixed integer tt so that μt=2−21−t>2−ε/4\mu_t=2-2^{1-t}>2-\varepsilon/4. For odd primes define at(ℓ)=min⁡{v2(ℓ−1),t}a_t(\ell)=\min\{v_2(\ell-1),t\}, let z=⌊A1/3⌋z=\lfloor A^{1/3}\rfloor, and set

Z(n)=∑ℓ≤z, ℓ odd primeℓ∤Qat(ℓ)1ℓ∣Nϵ+h.Z(n)=\sum_{\substack{\ell\le z,\ \ell\text{ odd prime}\\\ell\nmid Q}} a_t(\ell)1_{\ell\mid N_\epsilon+h}.

Every prime in this sum is coprime to Q/pϵQ/p_\epsilon. The single and pair divisibility probabilities over AA consecutive class members are 1/ℓ+O(1/A)1/\ell+O(1/A) and 1/(ℓℓ′)+O(1/A)1/(\ell\ell')+O(1/A). Therefore

EZ=∑ℓ≤zℓ∤Qat(ℓ)ℓ+Ot(z/A),Var⁡Z=Ot(ln⁡ln⁡z+z2/A).\mathbf E Z=\sum_{\substack{\ell\le z\\\ell\nmid Q}} \frac{a_t(\ell)}\ell+O_t(z/A),\qquad \operatorname{Var}Z=O_t(\ln\ln z+z^2/A).

Fixed-modulus prime reciprocal sums give ∑ℓ≤zat(ℓ)/ℓ=(μt+o(1))ln⁡ln⁡z\sum_{\ell\le z}a_t(\ell)/\ell=(\mu_t+o(1))\ln\ln z: write ata_t as the sum of the indicators ℓ≡1(mod2j)\ell\equiv1\pmod{2^j}, 1≤j≤t1\le j\le t. The deleted primes contribute at most Ot(ln⁡ln⁡(w+3)+M/P)=o(ln⁡ln⁡x)O_t(\ln\ln(w+3)+M/P)=o(\ln\ln x). Since xη/3≤A≤xx^\eta/3\le A\le x, one has ln⁡ln⁡z=ln⁡ln⁡x+Oη(1)\ln\ln z=\ln\ln x+O_\eta(1). Chebyshev now gives Z≥(2−ε)ln⁡ln⁡xZ\ge(2-\varepsilon)\ln\ln x with the asserted exceptional proportion, uniformly in the vertex and shift.

Finally write Nϵ+h=pϵauN_\epsilon+h=p_\epsilon^a u with pϵ∤up_\epsilon\nmid u. Then

φ(pϵ(Nϵ+h))G=pϵ−1G pϵaφ(u),\frac{\varphi(p_\epsilon(N_\epsilon+h))}{G} =\frac{p_\epsilon-1}{G}\,p_\epsilon^a\varphi(u),

whose valuation is at least Z(n)Z(n), since the primes counted by ZZ do not divide QQ and in particular are different from pϵp_\epsilon. This proves (8).

By (7), the cancelled levels satisfy K≤(1/ln⁡2+o(1))ln⁡ln⁡x<(2−ε)ln⁡ln⁡xK\le(1/\ln2+o(1))\ln\ln x<(2-\varepsilon)\ln\ln x for, say, ε=1/4\varepsilon=1/4. Thus each cancelled coordinate was already integral for almost all class members. This is a statement for each coordinate, with a uniform exceptional proportion. It does not assert simultaneous integrality of all MKMK coordinates when KK grows. Nor does it locate the remaining phase: non-integrality is weaker than a fixed distance from Z\mathbb Z, and even many non-integral terms can sum to an integer.

Two decompositions and their limits

The literal additive-prime identity used for ω\omega fails for φ\varphi even modulo powers of two. For a≥1a\ge1 and distinct odd primes r,sr,s with gcd⁡(a,rs)=1\gcd(a,rs)=1,

φ(ars)−φ(ar)−φ(as)+φ(a)=φ(a)(r−2)(s−2).(9)\varphi(ars)-\varphi(ar)-\varphi(as)+\varphi(a) =\varphi(a)(r-2)(s-2). \tag{9}

If h>v2(qφ(a))h>v_2(q\varphi(a)), its product with q2−hq2^{-h} is non-integral. Any expression for qφ(m)2−h(mod1)q\varphi(m)2^{-h}\pmod1 as a constant plus separate functions of the prime-power divisors of mm would have zero mixed difference on a,ar,as,arsa,ar,as,ars, contradicting (9). This excludes that exact additive identity on the four-point set. It excludes neither an approximate decomposition on a selected class nor terms involving several primes together.

The divisor expansion φ(m)=∑d∣mμ(d)m/d\varphi(m)=\sum_{d\mid m}\mu(d)m/d is exact, but its raw weighted pieces have size qm/(d2h)q m/(d2^h); they do not come with the source's uniform o(1)o(1) bound. Integer pieces can be removed and other pieces can cancel, so this size calculation is an unmet estimate rather than an impossibility theorem for a regrouped divisor expansion.

A character expansion exposes a different cost. Already for the unnormalized case, on the stratum v2(φ(m))=vv_2(\varphi(m))=v and for odd qq, put k=h−v≥3k=h-v\ge3. The function u↦e(qu/2k)u\mapsto e(qu/2^k) on odd residues modulo 2k2^k has 2k−22^{k-2} nonzero multiplicative-character coefficients, each of modulus 21−k/22^{1-k/2}, hence total coefficient mass 2k/2−12^{k/2-1}. To see this, an imprimitive character has zero Gauss sum by pairing uu and u+2k−1u+2^{k-1}. For a primitive character the square of the Gauss sum's modulus is 2k2^k: expansion of the square leaves only the residues 11 and 1+2k−11+2^{k-1}, on which its values are 11 and −1-1. Divide by the group order 2k−12^{k-1}. The odd part of φ(m)\varphi(m) is multiplicative, so each character composition is 1-bounded and multiplicative. The valuation stratum, the growing coefficient mass and the joint shifts still need control. This calculation is not a lower bound for every possible expansion.

The inspected Theorem 3.1 is a two-point estimate with either its real-valued equidistribution and prime-value assumptions (3.1)--(3.2), or its quantified non-pretentiousness assumption (3.3). Its scale parameter satisfies L≤ln⁡X\mathcal L\le\ln X; its progression modulus and shifts are O(Lc)O(\mathcal L^c) for a sufficiently small absolute c>0c>0, and it omits a quantitatively bounded exceptional set of scales. A direct application to the full class here is outside that range: (4) gives P≫ln⁡xP\gg\ln x and Q≥(P/2)M≫(ln⁡x)2Q\ge(P/2)^M\gg(\ln x)^2, whereas Q=O((ln⁡x)c)Q=O((\ln x)^c) would be required. Removing a forced prime factor or using a different representation needs a new reduction, with its hypotheses checked afresh.

More fundamentally, no decomposition and moment comparison yielding a fixed saving for ΨG,H\Psi_{G,H} has been obtained from these inputs. The source uses small additive prime pieces before invoking its correlation theorem. Formula (9) blocks the literal additive identity; the divisor and character expansions above supply no replacement estimate. This is the precise remaining gap, not a theorem that all correlation approaches fail.

Exact cancellation by dilation designs

A different arrangement of dilations could cancel more levels by equal arguments. There is a window bound for this particular mechanism. Arithmetic progressions with different strides need not be disjoint or meet only once; their intersection period is essential.

Proposition 4 (bounded coincidence count). Consider lines Li=∑h≥1ciφ(ni+dih)2−hL_i=\sum_{h\ge1}c_i\varphi(n_i+d_ih)2^{-h}, 1≤i≤M1\le i\le M, with nonzero rational cic_i, positive integer strides did_i, and integer offsets nin_i satisfying ni+di≥1n_i+d_i\ge1. Equal strides are required to have distinct offsets modulo that stride. On each line select any EE consecutive positive levels. For distinct strides put λij=dj/gcd⁡(di,dj)\lambda_{ij}=d_j/\gcd(d_i,d_j). Then the number of selected points on line ii that lie on no other line is at least

(E−∑j≠idj≠di⌈Eλij⌉)+.(10)\left(E-\sum_{\substack{j\ne i\\d_j\ne d_i}} \left\lceil\frac E{\lambda_{ij}}\right\rceil\right)^+. \tag{10}

In particular, if E≤λijE\le\lambda_{ij} for all pairs of distinct strides, there are at least M(E−M+1)+M(E-M+1)^+ unshared points in total. Their formal coefficients in ∑iLi\sum_iL_i are nonzero. If cic_i is an integer and a selected level exceeds v2(ci)v_2(c_i), that coefficient is also non-integral.

Proof. Membership of ni+dihn_i+d_ih in line jj requires dih≡nj−ni(moddj)d_ih\equiv n_j-n_i\pmod{d_j}. This congruence is either inconsistent or restricts hh to one residue modulo λij\lambda_{ij}. It therefore has at most ⌈E/λij⌉\lceil E/\lambda_{ij}\rceil solutions in EE consecutive levels. Requiring the corresponding index on line jj to be positive can only remove solutions. Equal strides contribute none by the offset assumption. A union bound gives (10). Unshared points on different lines are distinct, and each retains its single nonzero coefficient. □\square

The window restriction cannot be omitted. For n1=n2=0n_1=n_2=0, d1=2d_1=2, d2=3d_2=3, and E=6E=6, line 1 has two shared selected points and line 2 has three. There are only seven unshared pairs, fewer than M(E−M+1)=10M(E-M+1)=10. The two progressions share every positive multiple of six.

For the cube's distinct prime strides, λij=pj≥P/2\lambda_{ij}=p_j\ge P/2. In regime (4), any block of E=O(ln⁡x)E=O(\ln x) levels meets the required window restriction. In particular, the block K<h≤HK<h\le H of (5) has E=H−K=Θ(ln⁡x)E=H-K=\Theta(\ln x) while M=O(ln⁡x/ln⁡ln⁡x)=o(E)M=O(\ln x/\ln\ln x)=o(E). It retains at least M(E−M+1)M(E-M+1) unshared points. Dividing all weights by GG does not change this count. Thus coincidences of arguments alone do not annihilate the normalized truncated expression as a formal linear combination.

This does not show that the values of that expression at the totient are nonzero or far from integers. Divisibility of a totient can turn a non-integral weight into an integer term, and distinct totient arguments can satisfy arithmetic relations. Equal-stride lines in one residue class are also outside the statement; they include the ordinary-tail combinations of the odd scalar-kernel route. Small strides with repeated intersections, other level selections and selected representatives outside (4) remain separate possibilities.

The favorable-window mechanism

The earlier conditional theorem for ω\omega, [[../library/irrationality/pratt_2024_irrationality_prime_factor_series_under_prime/theorem_1_3|Pratt's Theorem 1.3]], uses a different mechanism. Its reduction takes N=n0QN=n_0Q with k2∣Qk^2\mid Q for all k≤K=⌊5log⁡log⁡log⁡x⌋k\le K=\lfloor5\log\log\log x\rfloor and n0Q/k+1n_0Q/k+1 prime for every such kk, so that the window values ω(N+k)=ω(k)+1\omega(N+k)=\omega(k)+1 are known exactly; the rest of its tail is o(1)o(1) because ω\omega is at most (log⁡log⁡x)2(\log\log x)^2 on the next 2log⁡log⁡x2\log\log x shifts by construction and O(log⁡x)O(\log x) beyond. The totient analogue of the exact window is φ(N+k)=φ(k)N/k\varphi(N+k)=\varphi(k)N/k. Its discarded positive tail cannot satisfy the analogous smallness bound.

Proposition 5. For every b≥1b\ge1 there is N0(b)N_0(b) such that no N≥N0(b)N\ge N_0(b) and K≥1K\ge1 satisfy both lcm⁡(1,…,K)∣N\operatorname{lcm}(1,\ldots,K)\mid N and b∑k>Kφ(N+k)2−k<1b\sum_{k>K}\varphi(N+k)2^{-k}<1.

Proof. By the bound φ(m)≥m/(1+log⁡2m)\varphi(m)\ge m/(1+\log_2m) of the dilation section, and since m/(1+log⁡2m)m/(1+\log_2m) is nondecreasing on the positive integers, $\sum_{k>K}\varphi(N+k)2^{-k}\ge(N+1)2^{-K}/(1+\log_2(N+1)) \ge N2^{-K}/(2+\log_2N)$. So the second condition forces K>log⁡2N−log⁡2(2+log⁡2N)+log⁡2bK>\log_2N-\log_2(2+\log_2N)+\log_2b. The first condition gives ψ(K)≤ln⁡N\psi(K)\le\ln N for the Chebyshev function ψ\psi, and ψ(K)=(1+o(1))K\psi(K)=(1+o(1))K by the prime number theorem, so K≤(ln⁡2+o(1))log⁡2NK\le(\ln2+o(1))\log_2N. These bounds are incompatible once NN is large. □\square

A window with exact values and a discarded positive tail below 1/b1/b therefore cannot use the cofactors kk. At a scale N=x1+o(1)N=x^{1+o(1)}, the positive-tail lower bound also forces K=Ω(ln⁡x)K=\Omega(\ln x). An extension asking for one distinct prime linear form at every position of such a window would be outside the range of Pratt's [[../library/irrationality/pratt_2024_irrationality_prime_factor_series_under_prime/conjecture_1_2|quantitative prime tuples conjecture]], which covers at most 100log⁡log⁡log⁡x100\log\log\log x forms with coefficients at most (log⁡log⁡x)100(\log\log x)^{100}. It does not supply that longer prescription. This excludes neither a selected arithmetic subfamily with a different certificate nor weighted cancellation or another use of a prime-tuples hypothesis.

Standing and reopening

The retained construction consists of the exact dilation and cube identities, the common-divisor normalization, and the full averaged bound (2). The prescribed-pairing weight calculation, the limitation (6) of its absolute tail bound, the progression valuation estimate (8), the bounded coincidence count (10), and the positive-tail obstruction of Proposition 5 have their stated scopes only. These are Plasma AI's author-recorded arguments, without independent review or a native tier. The finite examples are exposed in the proofs; no numerical evidence is needed for their implications.

The construction stops at a specific unproved estimate: a fixed saving in ∣Ee(ΨG,H(n))∣|\mathbf E e(\Psi_{G,H}(\mathbf n))| for an admissible family. Neither the literal additive-prime identity nor the raw divisor or character expansion supplies it. The normalization saves a factor GG but does not remove the logarithmic window in this absolute-bound regime. Coincidences alone leave formal coefficients; they do not settle the phase at actual totient values. No impossibility claim for all weighted, correlation or selected-subfamily arguments follows.

A reopening input would be a decomposition with moment bounds yielding a fixed phase saving, a direct saving for the normalized phase, or a signed-tail estimate that avoids the bound (3). A new identity among the actual totient values could also use the surviving formal coefficients. The independent [[research/leads/totient_binary_series/integer_interpolation/two_depth_carries|odd scalar-kernel construction]] remains open: no vector family of cost o(2J)o(2^J) is obtained here, and its equivalence with a phase criterion does not obstruct an arithmetic attack on it.

The external input and reading scope are as follows. Tao--Teräväinen's arXiv:2512.01739v2 is a preprint; its Theorem 3.1 was checked at statement depth, and the reduction in Sections 5.1--5.4 through Theorem 5.1 was followed in the held transcription. The later estimates proving that technical theorem are not imported. Pratt's arXiv:2409.15185 statement, Conjecture 1.2, Proposition 2.1 and the deduction of Theorem 1.3 from it were inspected in the held transcription; its prime-tuples hypothesis remains an assumption, and no proof of that hypothesis is claimed.

Proposition 3 uses the standard Turán--Kubilius and Brun--Titchmarsh inequalities. Their exact statements were checked in [[../library/unit_fractions/elsholtz_2013_counting_number_solutions_erdos_straus/_index|Elsholtz--Tao's arXiv:1107.1010v6]], Lemma A.2, p. 48, and (A.10), p. 49, including the page images. Their proofs remain external. The fixed-modulus reciprocal-prime asymptotic used there and in (8) is DLMF (27.11.9), version 1.2.8; only finitely many fixed moduli are used for each truncation. The prime number theorem used in Proposition 5 has the same disclosed external standing as on [[research/leads/totient_binary_series/integer_interpolation/phase_localization|the phase-localization page]]. These source statements and the elementary specializations above confer no independent acceptance on the target.