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Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

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Purpose and standing. This page draws the connections from the author-recorded reconstructions in the Problem 416 folder to the rest of the corpus. Each section names its exact target with the status the target's page records, states what the reconstructed mechanism gives when transported, with a proof where one is given here, states what it does not give and why, and names the next investigation with what each outcome would establish. Every new statement below is author-recorded, no status or tier changes, and each imported input keeps the standing its library page records. The statements were independently reviewed as they stood on 2026-09-28T13:50:48Z by seven focused reviews graded in the connections grade, which passes all seven and accepts ten corrections, C1--C10, since applied; it assigns no tier. After the review, the Target paragraphs of the Problem 417, 416, 821 and 51 sections were updated to the standing their problem pages record; no statement or proof changed. The literature was not searched beyond the held corpus, so no novelty is claimed for the statements proved here.

Notation. For real xx, T(x)T(x) is the set of totient values in [1,x][1,x] and V(x)=∣T(x)∣V(x)=|T(x)|, as on the reconstruction pages. Following Problem 417, V′(x)=#{φ(m):1≤m≤x}V'(x)=\#\{\varphi(m):1\le m\le x\} counts the distinct totients of the integers up to xx. For a totient vv let fmin⁡(v)f_{\min}(v) be its least preimage and r(v)=fmin⁡(v)/v≥1r(v)=f_{\min}(v)/v\ge1 its least-preimage ratio; for k≥1k\ge1 let V(x;k)V(x;k) be Ford's count of the totients in [1,x][1,x] all of whose preimages are divisible by kk, and S(k)S(k) the set of such totients. π(x)\pi(x) counts the primes up to xx, and c0>0c_0>0 is Chebyshev's constant, π(x)≥c0x/log⁡x\pi(x)\ge c_0x/\log x for x≥2x\ge2.

Imported inputs, at their standing.

  • (F) Ford's Theorem 1 in the form used on the preprint's page: V(x)=M(x)eE(x)V(x)=M(x)e^{E(x)} with ∣E(x)∣≤K|E(x)|\le K for x≥x1x\ge x_1, where M(x)=(x/log⁡x)eΨ(x)M(x)=(x/\log x)e^{\Psi(x)}, together with that page's Step 1 bound ∣ψc′(t)∣≤K′/t|\psi_c'(t)|\le K'/t for ψc(t)=Ψ(ct)\psi_c(t)=\Psi(c^t), log⁡(ct)≥ee\log(c^t)\ge e^e, with K′=2C+D+∣D+12−2C∣K'=2C+D+|D+\tfrac12-2C|. Refereed source at statement level; the derivative bound is author-recorded there.
  • (F8) Ford's Theorem 8 (card, §1.3 of the held conversion): if dd is a totient all of whose preimages are divisible by kk, then V(x;k)≫εd−1−εV(x)V(x;k)\gg_\varepsilon d^{-1-\varepsilon}V(x). Ford calls it a trivial corollary of the proof of Theorem 2, and the paper's §7 lists the witnesses d=218⋅257d=2^{18}\cdot257 for k∈{2,4,8}k\in\{2,4,8\}, d=54d=54 for k∈{3,9}k\in\{3,9\}, d=12500d=12500 for k=5k=5, d=294d=294 for k=7k=7 and d=110d=110 for k=11k=11, with none found for k=6k=6 or k=10k=10. Statement-level import; the witness d=54d=54 is verified below.
  • (W) The order of magnitude V(x)≍V′(x)V(x)\asymp V'(x). Page 7 of the held 17-page manuscript of Pollack, Pomerance and Treviño (card) states that Ford showed V(x)≍W(x)≍Z(x)V(x)\asymp W(x)\asymp Z(x) for large xx, with WW their name for V′V' and ZZ the main term of Theorem 1, citing §§4–5 of the corrected arXiv version of Ford's paper. Ford's theorems as held do not mention V′V', and Ford's §5 was not reread here, so (W) is imported as the cited authors' reading of Ford. A second route to V≪V′V\ll V' is Lemma 4.1(iii) of the same manuscript, reconstructed with two imported counts on the Problem 49 folder's page.
  • (KK) The write-up's Proposition 4.1, estimates (3)–(5), at the standing recorded on the Theorem 1.1 page: kernel acceptance of a Lean file that is not held, with no prose proof.

The search. The problems, research and theory trees were searched for Euler's function, totient values and preimages, the counting function VV and the sum-of-divisors analogs. The hits are the arithmetic-function problems named below, Problem 49 with its research folder, the irrationality problems 249, 250 and 252 with the claim L16, and pages where φ\varphi denotes another function. The library cards of the totient literature (Erdős 1935, Maier–Pomerance 1988, Ford 1998, Pollack–Pomerance–Treviño 2013, Graham–Holt–Pomerance 1999, Ford 2020, Li 2026, the Problem 694 note, Baker–Harman 1998 and Lichtman 2022) were read at card level, and the conversions of Ford 1998, Maier–Pomerance 1988 and the 2013 manuscript were read where they are cited.

Problem 417: the two counts of distinct totients

Target. Problem 417 asks whether lim⁡V(x)/V′(x)\lim V(x)/V'(x) exists and whether it is greater than 11. The page records the status open with no claim page, records the results of this section under its Progress, and records under its Current assessment Theorem 2.2 of the OpenAI release, which bears on the problem without claiming it; no status search was made here beyond the held corpus, whose only statements about V′V' are (W) and a remark of Maier and Pomerance recorded next. Write R(x)=V(x)/V′(x)R(x)=V(x)/V'(x) and V0(x)=V(x)−V′(x)V_0(x)=V(x)-V'(x). A notational trap: the closing section of Maier and Pomerance (card, §5 of the held conversion) writes V′(x)V'(x) for #{φ(n)≤x:n>x}\#\{\varphi(n)\le x:n>x\}, a different count of the same order as VV, and writes V0(x)V_0(x) for the cardinality of {φ(n)≤x:n>x}\{\varphi(n)\le x:n>x\} minus {φ(n):n≤x}\{\varphi(n):n\le x\}, which is the V0V_0 here; the authors call a lower bound for it a harder question that their methods do not give.

Lemma 417.1 (elementary facts, author-recorded).

  • (a) V′(x)=#{v∈T(x):fmin⁡(v)≤x}V'(x)=\#\{v\in T(x):f_{\min}(v)\le x\} and V0(x)=#{v∈T(x):fmin⁡(v)>x}V_0(x)=\#\{v\in T(x):f_{\min}(v)>x\}; hence R(x)≥1R(x)\ge1 and R(x)=R(⌊x⌋)R(x)=R(\lfloor x\rfloor).
  • (b) V′(n+1)−V′(n)∈{0,1}V'(n+1)-V'(n)\in\{0,1\} for integers nn, and V′(x)≥π(x)≥c0x/log⁡xV'(x)\ge\pi(x)\ge c_0x/\log x for x≥2x\ge2.
  • (c) For integers n≥2n\ge2, ∣R(n+1)−R(n)∣≤2n/V′(n)2≤(2/c02)(log⁡n)2/n|R(n+1)-R(n)|\le2n/V'(n)^2\le(2/c_0^2)(\log n)^2/n.

Proof. (a) Since φ(m)≤m\varphi(m)\le m, every value of an argument m≤xm\le x lies in T(x)T(x), and v∈T(x)v\in T(x) is such a value exactly when its least preimage is at most xx; both counts depend on xx through ⌊x⌋\lfloor x\rfloor. (b) Passing from nn to n+1n+1 adds one argument, hence at most one value; the primes p≤xp\le x give the distinct values φ(p)=p−1\varphi(p)=p-1. (c) Put A=V(n)A=V(n), B=V′(n)B=V'(n), δ=V(n+1)−V(n)∈{0,1}\delta=V(n+1)-V(n)\in\{0,1\} and ϵ=V′(n+1)−V′(n)∈{0,1}\epsilon=V'(n+1)-V'(n)\in\{0,1\}. Then R(n+1)−R(n)=(Bδ−Aϵ)/(B(B+ϵ))R(n+1)-R(n)=(B\delta-A\epsilon)/(B(B+\epsilon)), so ∣R(n+1)−R(n)∣≤(B+A)/B2≤2A/B2≤2n/B2|R(n+1)-R(n)|\le(B+A)/B^2\le2A/B^2\le2n/B^2, using B≤A≤nB\le A\le n; (b) gives the last bound. □\square

Proposition 417.2 (the cluster interval; transfer of Step 7). Let α=lim inf⁡nR(n)\alpha=\liminf_nR(n) and β=lim sup⁡nR(n)\beta=\limsup_nR(n) over the integers, in [1,∞][1,\infty]. The set of subsequential limits of R(n)R(n) is the closed interval [α,β][\alpha,\beta], the same set is obtained as x→∞x\to\infty through the reals, and β<∞\beta<\infty under (W). Consequently exactly one of the following holds: R(x)R(x) converges; or RR has continuum many limit points.

Proof. By Lemma 417.1(c) the adjacent variation ∣R(n+1)−R(n)∣|R(n+1)-R(n)| tends to 00. Step 7 of the preprint's page uses nothing else: for finite yy with α<y<β\alpha<y<\beta and any n0n_0 there are n1,n2>n0n_1,n_2>n_0 with R(n1)<y<R(n2)R(n_1)<y<R(n_2), and the last index nn of the block between them on the initial side of yy has yy between R(n)R(n) and R(n+1)R(n+1), so ∣R(n)−y∣≤(2/c02)(log⁡n0)2/n0|R(n)-y|\le(2/c_0^2)(\log n_0)^2/n_0; letting n0→∞n_0\to\infty makes yy a limit point. The endpoints are limit points by definition, finite or not, and the cluster set is closed, so it is [α,β][\alpha,\beta]. By 417.1(a), R(x)=R(⌊x⌋)R(x)=R(\lfloor x\rfloor), so the real and integer cluster sets coincide. Under (W), RR is bounded and β<∞\beta<\infty. If α=β\alpha=\beta the sequence converges; if α<β\alpha<\beta the interval is nondegenerate, hence uncountable. □\square

Nothing about totients enters beyond the unit jumps and the trivial lower bound for V′V': this is the preprint's Lemma 3.1 and Theorem 3.4 with V′V' in the denominator.

Theorem 417.3 (the ratio exceeds one infinitely often; author-recorded). There is η>0\eta>0 such that V0(x)≥ηV(x)V_0(x)\ge\eta V(x) for arbitrarily large xx. Hence β=lim sup⁡xR(x)≥1/(1−η)>1\beta=\limsup_xR(x)\ge1/(1-\eta)>1, and if the limit asked for in Problem 417 exists, it exceeds 11.

Inputs: (F), (F8) with k=3k=3 and d=54d=54, and Chebyshev's bound.

Proof. Step 1, the witness. The preimages of 5454 are exactly 8181 and 162162. If φ(m)=54=2⋅33\varphi(m)=54=2\cdot3^3 with mm odd and 3∣m3\mid m, write m=3tm′′m=3^tm'' with m′′m'' odd and 3∤m′′3\nmid m''; then φ(m)=2⋅3t−1φ(m′′)\varphi(m)=2\cdot3^{t-1}\varphi(m'') forces φ(m′′)=34−t\varphi(m'')=3^{4-t}, an odd value, so m′′=1m''=1, t=4t=4 and m=81m=81. If mm is odd and 3∤m3\nmid m, each odd prime factor qq of mm contributes the even factor q−1q-1 to φ(m)\varphi(m), so m=qem=q^e for one odd prime qq with qe−1(q−1)=54q^{e-1}(q-1)=54, which forces e=1e=1 and q=55q=55, not prime (e=2e=2 has no solution and e≥3e\ge3 needs q2∣54q^2\mid54). If m=2bm′m=2^bm' is even with m′m' odd and b≥1b\ge1, then φ(m)=2b−1φ(m′)\varphi(m)=2^{b-1}\varphi(m'); as 5454 carries one factor 22 and φ(m′)\varphi(m') is even unless m′=1m'=1, which gives a power of 22, we get b=1b=1, φ(m′)=54\varphi(m')=54 with m′m' odd, m′=81m'=81 and m=162m=162. Both preimages are divisible by 33, so (F8) with k=3k=3 gives c>0c>0 and x0x_0 with V(x;3)≥cV(x)V(x;3)\ge cV(x) for x≥x0x\ge x_0.

Step 2, the least preimage on S=S(3)S=S(3). If every preimage mm of vv is divisible by 33, then m/φ(m)≥3/2m/\varphi(m)\ge3/2 for each, so fmin⁡(v)≥32vf_{\min}(v)\ge\tfrac32v. Hence every v∈Sv\in S with 2x/3<v≤x2x/3<v\le x has fmin⁡(v)>xf_{\min}(v)>x, and by 417.1(a)

V0(x) ≥ N(x):=#{v∈S: 2x/3<v≤x}.V_0(x)\ \ge\ N(x):=\#\{v\in S:\ 2x/3<v\le x\}.

Step 3, a geometric decomposition. Put λ=3/2\lambda=3/2. The intervals (x/λj+1,x/λj](x/\lambda^{j+1},x/\lambda^j], j≥0j\ge0, partition (0,x](0,x], so

V(x;3)=∑j≥0N(x/λj),V(x;3)=\sum_{j\ge0}N(x/\lambda^j),

a finite sum since 1∉S1\notin S (its preimage 11 is not divisible by 33) and so N(z)=0N(z)=0 for z<2z<2.

Step 4, the sum of VV along the geometric sequence. There is a constant C1C_1, depending only on Ford's constants, with ∑j≥0V(x/λj)≤(3C1+o(1))V(x)\sum_{j\ge0}V(x/\lambda^j)\le(3C_1+o(1))V(x). For the jj with z=x/λj≥x1/2z=x/\lambda^j\ge x^{1/2} and xx large, (F) gives

V(z)V(x)≤e2K zx log⁡xlog⁡z eΨ(z)−Ψ(x)≤2e2Kλ−jeΨ(z)−Ψ(x),\frac{V(z)}{V(x)}\le e^{2K}\,\frac zx\,\frac{\log x}{\log z}\, e^{\Psi(z)-\Psi(x)}\le2e^{2K}\lambda^{-j}e^{\Psi(z)-\Psi(x)},

and with x=λtx=\lambda^t, z=λt′z=\lambda^{t'}, t′≥t/2t'\ge t/2, the derivative bound of (F) gives

∣Ψ(z)−Ψ(x)∣=∣ψλ(t′)−ψλ(t)∣≤K′log⁡(t/t′)≤K′log⁡2.|\Psi(z)-\Psi(x)|=|\psi_\lambda(t')-\psi_\lambda(t)|\le K'\log(t/t')\le K'\log2.

So V(x/λj)≤C1λ−jV(x)V(x/\lambda^j)\le C_1\lambda^{-j}V(x) with C1=21+K′e2KC_1=2^{1+K'}e^{2K}, and these jj contribute at most C1V(x)/(1−1/λ)=3C1V(x)C_1V(x)/(1-1/\lambda)=3C_1V(x). The remaining jj, at most log⁡λx+1\log_\lambda x+1 of them, have V(x/λj)≤x/λj≤x1/2V(x/\lambda^j)\le x/\lambda^j\le x^{1/2}, contributing O(x1/2log⁡x)=o(V(x))O(x^{1/2}\log x)=o(V(x)) by V(x)≥π(x+1)≥c0x/log⁡xV(x)\ge\pi(x+1)\ge c_0x/\log x.

Step 5, conclusion. Suppose N(y)≤ηV(y)N(y)\le\eta V(y) for all y≥y0y\ge y_0, with η=c/(6C1)\eta=c/(6C_1). For x≥y0x\ge y_0 the blocks with x/λj<y0x/\lambda^j<y_0 lie in (0,y0)(0,y_0) and contribute at most V(y0)V(y_0) to the sum of Step 3, so

V(x;3)≤η∑j≥0V(x/λj)+V(y0)≤(c2+o(1))V(x)+V(y0)<cV(x)V(x;3)\le\eta\sum_{j\ge0}V(x/\lambda^j)+V(y_0) \le\bigl(\tfrac c2+o(1)\bigr)V(x)+V(y_0)<cV(x)

for large xx, contradicting Step 1. Hence N(y)>ηV(y)N(y)>\eta V(y) for arbitrarily large yy, and for those yy, V′(y)=V(y)−V0(y)≤(1−η)V(y)V'(y)=V(y)-V_0(y)\le(1-\eta)V(y), that is R(y)≥1/(1−η)R(y)\ge1/(1-\eta). The last sentence of the statement is Proposition 417.2: if the limit exists it equals β\beta. □\square

Remarks. (i) The constant η=c/(6C1)\eta=c/(6C_1) depends on the implied constant of (F8) at d=54d=54 and on Ford's O(1)O(1), neither of which is explicit, so η\eta is not numerical. (ii) Any of Ford's witnesses serves. With k=4k=4 and d=218⋅257d=2^{18}\cdot257 one has fmin⁡(v)≥2vf_{\min}(v)\ge2v on S(4)S(4), the blocks are dyadic, and the doubling law of the Theorem 1.1 page replaces Step 4 by ∑jV(x/2j)∼2V(x)\sum_jV(x/2^j)\sim2V(x); the proof above uses only the refereed inputs. (iii) The mechanism is the lower bound on every preimage that the sets S(k)S(k) carry; the reconstructed pages supply the bookkeeping (unit jumps for 417.2, the derivative bound for Step 4) and not the arithmetic.

Proposition 417.4 (conditional). If N(y)≥η′V(y)N(y)\ge\eta'V(y) for all large yy, then lim inf⁡R≥1/(1−η′)>1\liminf R\ge1/(1-\eta')>1. The premise is the short-interval form of (F8); Ford's Theorem 4, which Ford obtains by a simple modification of the proofs of Theorems 1 and 2 and which gives Vk(x+y)−Vk(x)≍(y/(x+y))V(x+y)V_k(x+y)-V_k(x)\asymp(y/(x+y))V(x+y) for y≥xθy\ge x^\theta and possible multiplicities kk, makes the same localization plausible for V(x;k)V(x;k), but the held paper does not state it. Proof. Immediate from Step 2. □\square Neither this nor Theorem 417.3 decides whether the limit exists.

What it does not give.

  • The existence of the limit. Steps 1–6 of the preprint's argument locate cc as a limit point through log⁡V(ct)=tlog⁡c+ηc(t)+O(1)\log V(c^t)=t\log c+\eta_c(t)+O(1) and the exact telescoping of consecutive quotients. R=V/V′R=V/V' compares two functions at one scale, no product of consecutive values of RR telescopes, and no asymptotic for V′V' beyond (W) is held, so no candidate value is produced and the near-hit mechanism does not transfer.
  • The pair family. A retained pair (b,p)(b,p) with core b=φ(m0)b=\varphi(m_0) from a record m0=a∏jpjm_0=a\prod_jp_j gives the value v=b(p−1)v=b(p-1) the preimage m0pm_0p, so fmin⁡(v)≤(m0/b) (p/(p−1)) vf_{\min}(v)\le(m_0/b)\,(p/(p-1))\,v. If the retained records had m0/φ(m0)≤K(ε)m_0/\varphi(m_0)\le K(\varepsilon) (plausible from the record conditions, which resemble the spacing conditions under which Lemma 4.1(iii) of the Problem 49 folder bounds n/φ(n)n/\varphi(n), but stated in no held text), then all but (ε+o(1))V(y)(\varepsilon+o(1))V(y) totients v≤yv\le y would satisfy fmin⁡(v)≤2K(ε)vf_{\min}(v)\le2K(\varepsilon)v, which gives again only R≪1R\ll1: an upper bound on least preimages cannot produce the lower bounds that V0V_0 counts.

Reformulation and finite-range numbers (exploratory). By 417.1(a), V0(x)=#{v∈T(x):r(v)>x/v}V_0(x)=\#\{v\in T(x):r(v)>x/v\}, so the limit in Problem 417 is a statement about the joint distribution of v/xv/x and r(v)r(v) over the totients v≤xv\le x. Suppose (H1) V(ux)/V(x)→uV(ux)/V(x)\to u for each fixed u∈(0,1]u\in(0,1], the general-scale law of the next section, known only for uu a power of 1/21/2; and (H2) for each fixed u∈(0,1]u\in(0,1] and t≥1t\ge1, #{v≤ux:r(v)≤t}/V(ux)→G(t)\#\{v\le ux:r(v)\le t\}/V(ux)\to G(t) for a nondecreasing function GG on [1,∞)[1,\infty) with values in [0,1][0,1]. Then, bracketing the indicator 1[r(v)≤x/v]1[r(v)\le x/v] on (ui−1x,uix](u_{i-1}x,u_ix] between 1[r(v)≤1/ui]1[r(v)\le1/u_i] and 1[r(v)≤1/ui−1]1[r(v)\le1/u_{i-1}] over a grid and refining it,

V′(x)V(x)→∫01G(1/u) du,V0(x)V(x)→∫1∞(1−G(t))dtt2,\frac{V'(x)}{V(x)}\to\int_0^1G(1/u)\,du,\qquad \frac{V_0(x)}{V(x)}\to\int_1^\infty\bigl(1-G(t)\bigr)\frac{dt}{t^2},

and R(x)R(x) converges to the reciprocal of the first integral. This is a frame, not a route: it names the two limits it assumes, and (H2) is exactly the least-preimage distribution that no held source studies.

A computation made for this page sieves Euler's function for all n≤6.2⋅107n\le6.2\cdot10^7, which covers every preimage of every totient v≤107v\le10^7: an integer with at most nine distinct prime factors has n/φ(n)≤∏p≤23p/(p−1)<6.12n/\varphi(n)\le\prod_{p\le23}p/(p-1)<6.12, and one with ten or more has φ(n)≥φ(2⋅3⋅5⋯29)>109\varphi(n)\ge\varphi(2\cdot3\cdot5\cdots29)>10^9. It gives, as (x;V(x),V′(x),V0(x);R(x))(x;V(x),V'(x),V_0(x);R(x)): (104;2374,2160,214;1.0991)(10^4;2374,2160,214;1.0991), (105;20254,18412,1842;1.1000)(10^5;20254,18412,1842;1.1000), (106;180184,163861,16323;1.0996)(10^6;180184,163861,16323;1.0996) and (107;1634372,1485793,148579;1.1000)(10^7;1634372,1485793,148579;1.1000), so V0/VV_0/V is 0.09010.0901, 0.09090.0909, 0.09060.0906 and 0.09090.0909. Every totient v≤107v\le10^7 has r(v)≤2.0414r(v)\le2.0414, the maximum at v=2037248=φ(3⋅5⋅17⋅47⋅347)v=2037248=\varphi(3\cdot5\cdot17\cdot47\cdot347) with fmin⁡(v)=4158795f_{\min}(v)=4158795 (up to 10610^6 the maximum is 2.03552.0355 at v=5888=φ(3⋅5⋅17⋅47)v=5888=\varphi(3\cdot5\cdot17\cdot47)), so in this range every element counted by V0(x)V_0(x) lies in (x/2.0414,x](x/2.0414,x], and only the ten totients v≤107v\le10^7 with r(v)>2r(v)>2 (58885888, 1049610496, 1740817408, 276736276736, 20372482037248, 52689925268992, 53319685331968, 69831686983168, 80430088043008 and 87495688749568) can fall in (x/2.0414,x/2](x/2.0414,x/2]. Among the totients in (5⋅106,107](5\cdot10^6,10^7] the proportions with r(v)≥1.1r(v)\ge1.1, 1.251.25, 1.51.5 and 22 are 0.3190.319, 0.2660.266, 0.1940.194 and 0.000010.00001. The sets behind Theorem 417.3 are far smaller than V0V_0: V(107;3)/V(107)≈0.0013V(10^7;3)/V(10^7)\approx0.0013, and no totient up to 10710^7 has all preimages divisible by 44 (Ford's witness 218⋅2572^{18}\cdot257 exceeds 10710^7). The near-constancy R(x)≈1.10R(x)\approx1.10 over three decades is a finite observation that proves nothing about the limit; it is recorded as the value a limit-existence proof would have to meet.

Next investigation.

  1. The short-interval form of (F8): show V(x;3)−V(2x/3;3)≫V(x)V(x;3)-V(2x/3;3)\gg V(x), or the k=4k=4 form on (x/2,x](x/2,x], by localizing Ford's §5 construction as Ford's Theorem 4 does for VkV_k. A positive outcome makes Proposition 417.4 unconditional, R(x)≥1+η′R(x)\ge1+\eta' for all large xx; a negative one, a proof that S(3)∩(2x/3,x]S(3)\cap(2x/3,x] is o(V(x))o(V(x)) along a sequence, would mean (F8) is carried by other blocks at those scales and would send the argument to another witness set.
  2. The limit itself: prove or refute a limiting law (H2) for r(v)r(v) over totients, for which Ford's Theorems 10–11 and the classification by V(x;k)/V(x)V(x;k)/V(x) Ford proposes for the asymptotic formula are the tools. No support bound is available: by (F8) at k=4k=4 with Ford's witness 218⋅2572^{18}\cdot257, every v∈S(4)v\in S(4) other than a power of 22 has r(v)>2r(v)>2, since its least preimage mm has 4∣m4\mid m and an odd prime factor, so m/φ(m)>2m/\varphi(m)>2; hence 1−G(2)≥c4>01-G(2)\ge c_4>0 for any limiting GG, and the law to prove or refute is (H2) without a support bound. With (H1) this gives the limit and its value through the frame above; a proof that V0(x)/V(x)V_0(x)/V(x) oscillates answers the first question negatively and, by 417.2, gives continuum many limit points.
  3. Extend the computation to 10910^9–101010^{10} by a segmented sieve of least preimages, on the model of the preprint's §8 computation of VV: a drift of RR away from 1.101.10 would show that the observed constancy is a small-range effect.

Outcome. Transfers in part: the cluster-interval structure transfers with proof (Proposition 417.2), and the ratio exceeds 11 infinitely often (Theorem 417.3), so the second question's answer is yes whenever the first's is; the existence of the limit is untouched. Filed as the lead distinct_totient_preimage_ratio.

Problem 416 at a general scale: the accepted family with another balance

Target. The variant of Problem 416 that Erdős posed with it, V(cx)/V(x)→cV(cx)/V(x)\to c for every fixed c>1c>1, recorded in Guy's B36 (card) and in §1.2 of Ford's paper, which says that the method of the paper's Theorem 1 falls short of it. It is not a clause of the erdosproblems.com statement, whose first question is c=2c=2, answered as the problem page records, and whose second is the asymptotic formula; the problem page records the standing claimed, through the OpenAI release's pending full claim on the second question. The variant itself is settled: the problem page records the same release's fixed-scale law, V(cx)/V(x)→cV(cx)/V(x)\to c for every fixed real c>0c>0, as an accepted partial claim on its built and audited Lean declaration. It supersedes this section's reduction as a route to the variant, as the closed lead general_scale_totient_doubling records; the reduction stays recorded below. Before the release, the only claim for c≠2c\ne2 was the preprint's, reconstructed in this folder: cc is a limit point of V(cn)/V(n)V(cn)/V(n) and the cluster set is a closed interval of unknown width; the integer powers of 22 are settled by the accepted doubling law by telescoping, as recorded below.

What transports. The prose deduction of the doubling law uses c=2c=2 in exactly one place, the balance estimate (5). Two lemmas make this precise.

Lemma 416.1 (finite counting inequality at scale cc). In the setting of the Lemma 2.1 page (finite T0⊆TT_0\subseteq T, f ⁣:P→Tf\colon P\to T, P0=f−1(T0)P_0=f^{-1}(T_0), and the counts M,M0,E,E0M,M_0,E,E_0), for every real c≥1c\ge1,

∣ ∣T∣−c∣T0∣ ∣≤∣ ∣P∣−c∣P0∣ ∣+max⁡(1,c−1) (M+E).\bigl|\,|T|-c|T_0|\,\bigr|\le\bigl|\,|P|-c|P_0|\,\bigr|+\max(1,c-1)\,(M+E).

Proof. The exact identity of that page reads ∣T∣−c∣T0∣=(∣P∣−c∣P0∣)+(M−cM0)−(E−cE0)|T|-c|T_0|=(|P|-c|P_0|)+(M-cM_0)-(E-cE_0). Since 0≤M0≤M0\le M_0\le M, the number M−cM0M-cM_0 lies in [−(c−1)M,M][-(c-1)M,M], so ∣M−cM0∣≤max⁡(1,c−1)M|M-cM_0|\le\max(1,c-1)M; likewise for EE. □\square For 1≤c≤21\le c\le2 the constant is 11, and c=2c=2 is that page's display (2).

Lemma 416.2 (relative error controls the quotient at scale cc). If v>0v>0, w≥0w\ge0, 0≤δ≤1/20\le\delta\le1/2 and ∣w−cv∣≤δw|w-cv|\le\delta w, then ∣w/v−c∣≤2cδ|w/v-c|\le2c\delta.

Proof. From (1−δ)w≤cv(1-\delta)w\le cv and δ≤1/2\delta\le1/2, w≤2cvw\le2cv, so ∣w/v−c∣=∣w−cv∣/v≤δw/v≤2cδ|w/v-c|=|w-cv|/v\le\delta w/v\le2c\delta. □\square

Proposition 416.3 (conditional general-scale law). Fix c>1c>1. Suppose that for every 0<ε<1/20<\varepsilon<1/2 there are retained families (Py,fy)(P_y,f_y), one for each large real yy, satisfying (3) and (4) of Proposition 4.1 and

(5c)Ay−cBy(c)=o(Ay),By(c)=#{a∈Py: fy(a)≤y/c}.\text{(5}_c\text{)}\qquad A_y-cB^{(c)}_y=o(A_y),\qquad B^{(c)}_y=\#\{a\in P_y:\ f_y(a)\le y/c\}.

Then V(cx)/V(x)→cV(cx)/V(x)\to c as real x→∞x\to\infty.

Proof. Follow Steps 1–5 of the Theorem 1.1 page with T0=T(y/c)T_0=T(y/c). Step 1 is Lemma 416.1, with ∣P∣−c∣P0∣=Ay−cBy(c)=:Dy(c)|P|-c|P_0|=A_y-cB^{(c)}_y=:D^{(c)}_y because P0=fy−1(T(y/c))P_0=f_y^{-1}(T(y/c)) is the set of pairs with value at most y/cy/c. Step 2 is unchanged. Step 3 gives Dy(c)=o(V(y))D^{(c)}_y=o(V(y)) from (5c_c) and Ay≤2V(y)A_y\le2V(y). In Step 4, for a given δ>0\delta>0 choose ε<min⁡(1/2,δ/(2max⁡(1,c−1)))\varepsilon<\min(1/2,\delta/(2\max(1,c-1))); then ∣V(y)−cV(y/c)∣≤max⁡(1,c−1)εV(y)+o(V(y))≤δV(y)|V(y)-cV(y/c)|\le\max(1,c-1)\varepsilon V(y)+o(V(y))\le\delta V(y) for all large yy, that is ∣V(cx)−cV(x)∣≤δV(cx)|V(cx)-cV(x)|\le\delta V(cx). Step 5 is Lemma 416.2 with w=V(cx)w=V(cx), v=V(x)v=V(x) and δ=min⁡(1/2,η/(4c))\delta=\min(1/2,\eta/(4c)), giving ∣V(cx)/V(x)−c∣≤η/2|V(cx)/V(x)-c|\le\eta/2. □\square

Two remarks. First, (3) and (4) do not mention cc: they concern one family at one scale. So the family the accepted file constructs, whose (3) and (4) are the kernel-accepted declarations named on the Theorem 1.1 page, serves for every cc, and the general-scale law at a given cc reduces, at that standing, to the single balance statement (5c_c) for that family. Second, per the write-up's §4.3 as read on the Theorem 1.1 page, (5) comes from a common mass H(y)H(y) with Ay/H(y)→1A_y/H(y)\to1 and By/H(y)→1/2B_y/H(y)\to1/2 over cores bb with log⁡b≤G(y)=o(log⁡y)\log b\le G(y)=o(\log y); if the pairs above a core bb are the primes pp in an interval whose upper end is y/by/b for p−1p-1, so that b(p−1)≤yb(p-1)\le y, then the c=2c=2 balance forces the lower ends of these intervals to be negligible in aggregate, and By(c)/H(y)→1/cB^{(c)}_y/H(y)\to1/c by the same uniformity of the prime number theorem (π(u/c)/π(u)→1/c\pi(u/c)/\pi(u)\to1/c uniformly for u≥y1−o(1)u\ge y^{1-o(1)}), so (5c_c) holds for every c>1c>1. Whether the accepted development counts in this way is not established: the file is not held, and the mass is defined only there.

What the accepted c=2c=2 law adds without any premise, for c=21/mc=2^{1/m} with m≥2m\ge2: the exact identity ∏j=0m−1Rc(cjx)=V(2x)/V(x)→2\prod_{j=0}^{m-1}R_c(c^jx)=V(2x)/V(x)\to2 shows that the geometric mean of RcR_c over any mm consecutive scales tends to cc, a finite-block form of the preprint's Step 2 with no error term. As in the preprint this yields near-hits and no width control; for m=2m=2 it forces αcβc=2\alpha_c\beta_c=2 for the reconstructed cluster interval [αc,βc][\alpha_c,\beta_c] (a sequence realizing αc\alpha_c at xx realizes 2/αc2/\alpha_c at cxcx, and symmetrically), which does not make the interval degenerate. For c=2mc=2^m with an integer m≥2m\ge2 the same telescoping settles the variant outright at the standing of the accepted file: V(2mx)/V(x)=∏i=0m−1V(2i+1x)/V(2ix)→2mV(2^mx)/V(x)=\prod_{i=0}^{m-1}V(2^{i+1}x)/V(2^ix)\to2^m as real x→∞x\to\infty, so the cluster set is {c}\{c\}; and for c=2k/mc=2^{k/m} the product of RcR_c over mm consecutive scales tends to 2k2^k.

What it does not give. No asymptotic formula, since the mass depends on ε\varepsilon as the Theorem 1.1 page explains; no rate; nothing for cc outside the integer powers of 22 until (5c_c) is verified, so the preprint's dichotomy stands for every c>1c>1 that is not an integer power of 22; and no prose proof, since (3) and (4) keep the standing of the accepted file.

Next investigation. Obtain the accepted file (its URL, size and hash are on the write-up's card), read the definition of the pair family, the mass H(y)H(y) and the declaration power_corePairs_count_asymptotic (line 63482 in the write-up's map) with its dependencies, and determine whether the top-prime ranges and the count are scale-free. A positive outcome gives (5c_c) for every c>1c>1 by the same argument, hence V(cx)∼cV(x)V(cx)\sim cV(x) for all c>1c>1 at the standing of the accepted file plus an author-checked generalization, collapsing the reconstructed cluster interval to {c}\{c\} for every cc; a negative one closes this route: (5c_c) for the accepted family would then need an argument of its own, or a differently balanced family with its own estimates (3)–(5).

Outcome. Transfers conditionally, with the premise (5c_c) explicit. Filed as the lead general_scale_totient_doubling.

Problem 821: large fibers versus repeated representations

Target. Problem 821: with g(n)=#{m:φ(m)=n}g(n)=\#\{m:\varphi(m)=n\}, is g(n)>n1−ϵg(n)>n^{1-\epsilon} for infinitely many nn, for every ϵ>0\epsilon>0? Its page records the standing claimed, with the question proved, through the OpenAI release's pending full claim of 24 September 2026, beside Baker and Harman's accepted partial claim and Lichtman's pending one. Its references record the chain from Erdős 1935 (some positive exponent) through Baker–Harman 1998 (values with more than m1−βm^{1-\beta} preimages, β=0.2961\beta=0.2961, Corollary 1 on the card) to Lichtman 2022 (values with at least m0.7156m^{0.7156} preimages, Corollary 1.3 on the card), all from smooth shifted primes; the gap the accepted results leave is the exponent 1−ϵ1-\epsilon for every ϵ\epsilon.

What the mechanism gives, and why it is nothing. The collision estimate (4) bounds ∑t(∣fy−1(t)∣−1)\sum_t(|f_y^{-1}(t)|-1) over the fibers of the pair map fy(b,p)=b(p−1)f_y(b,p)=b(p-1). The fiber over a value tt consists of pairs (b,p)(b,p) with pp prime and p−1∣tp-1\mid t, so ∣fy−1(t)∣≤#{p:p−1∣t}≤d(t)=to(1)|f_y^{-1}(t)|\le\#\{p:p-1\mid t\}\le d(t)=t^{o(1)} for every family. Problem 821 concerns g(t)g(t), which the sources above show exceeds t0.7t^{0.7} infinitely often. Two preimages m,m′m,m' with the same top prime pp and cores of equal totient, φ(m/p)=φ(m′/p)\varphi(m/p)=\varphi(m'/p), are one pair, so the pair count of a value collapses its fiber under φ\varphi to a divisor-bounded number. Hence (4) is a statement about a quantity that is to(1)t^{o(1)} for every value, neither implying nor implied by a bound on gg; the coverage (3) concerns which values are represented, not how often; and the direction of Problem 821, lower bounds for extreme fibers, is the opposite of what a family built to keep fibers small on average can supply. Ford's Theorem 2, a positive proportion of totients for every possible multiplicity, is consistent with (4) for the same reason.

Next investigation. None through this mechanism; the route on the problem page is the smooth-shifted-prime one and does not count the value set.

Outcome. Fails: different objects, pair representations bounded by the divisor function against preimages.

Problem 694: the extreme fiber ratio

Target. Problem 694 asks for max⁡fmax⁡(n)/fmin⁡(n)\max f_{\max}(n)/f_{\min}(n) over totient values n≤xn\le x. The page records the erdosproblems.com status solved (Lean), qualified: the asymptotic (eγ+o(1))log⁡log⁡x(e^\gamma+o(1))\log\log x rests on a five-page note (Theorem 2.1 on its card) and two external Lean developments read as text, with no refereed publication or independent review held.

What the mechanism gives. Nothing for the question: fmax⁡f_{\max} is invisible to the pair family, whose pairs each supply one preimage, and the extreme ratio comes from the extreme fibers that (3)–(5) average away. What it would give under the unverified bounded-record premise of the Problem 417 section is a typical-ratio statement, fmin⁡(v)≤K(ε)vf_{\min}(v)\le K(\varepsilon)v for all but an ε\varepsilon-proportion of totients, which no erdosproblems.com problem asks and which is the object of Problem 417. The one shared device is the existence half of the multiplication by convenient integers behind Ford's Theorem 8 and the Problem 49 folder's Lemma 4.1: the note's Proposition 3.1 observes that a collision φ(a)=φ(b)=n\varphi(a)=\varphi(b)=n gives (r−1)n(r-1)n the preimages rara and rbrb for every prime r∤abr\nmid ab, and needs nothing about the other preimages of (r−1)n(r-1)n, whose absence is what convenient means. The witness d=54d=54 of Theorem 417.3 does not propagate this way: 54(r−1)54(r-1) lies in S(3)S(3) only when rr is convenient for 5454, and 54⋅(5−1)=216=φ(7⋅37)54\cdot(5-1)=216=\varphi(7\cdot37) shows that r=5r=5 is not; the propagation Theorem 417.3 would need is the exact-preimage clause of Ford's §7, which is Theorem 8 itself.

Outcome. Fails: no bearing on a solved question; the shared device is Ford's, not the reconstructions'.

Problem 51: the least-preimage ratio

Target. Problem 51: is there an infinite set AA of totients with fmin⁡(a)/a→∞f_{\min}(a)/a\to\infty along AA? Its page records the status open, with a rejected full claim and Guy's B36 form of the question (for every ϵ\epsilon an nn with φ(n)=m<ϵn\varphi(n)=m<\epsilon n and no smaller preimage of mm).

Reformulation (author-recorded). Problem 51 has a positive answer if and only if rr is unbounded on the totients. If totients vKv_K with r(vK)>Kr(v_K)>K exist for every KK, then, each r(v)r(v) being a finite number, only finitely many KK share a given vKv_K, so an increasing subsequence with r→∞r\to\infty is a set AA; the converse is the definition.

What the mechanism gives. Nothing: the pair family gives upper bounds fmin⁡(v)≤m0pf_{\min}(v)\le m_0p on covered values, and Problem 51 needs lower bounds. The one lower-bound device available, the sets S(k)S(k) of the Problem 417 section, gives r(v)≥k/φ(k)r(v)\ge k/\varphi(k) on S(k)S(k) and reaches r→∞r\to\infty only through moduli kk with many prime factors, that is, only if V(x;k)>0V(x;k)>0 for such kk. Ford's §7 finds witnesses for k≤11k\le11 only at the prime powers and at k=11k=11, none for 66 or 1010, and writes that there may be no totient all of whose preimages are divisible by 66 (its nonexistence would imply Carmichael's conjecture, since a totient with a unique preimage has that preimage divisible by 66). So the S(k)S(k) device is capped at the ratio 22 of k∈{2,4,8}k\in\{2,4,8\} unless a modulus kk with k/φ(k)>2k/\varphi(k)>2 admits a witness, that is, an even modulus with an odd prime factor (the least are 66, ratio 33, and 1010, ratio 5/25/2) or an odd modulus with at least three distinct prime factors, small enough (the least is 105105, ratio 35/1635/16; two odd primes give at most 15/815/8). No held source or computation supplies one. Moduli with two or three distinct odd prime factors do admit witnesses in the sieve's range (580580, with preimages 649=11⋅59649=11\cdot59 and 12981298 only; 116964116964, with preimages 33⋅1933^3\cdot19^3 and its double, ratio 19/1219/12; 103240103240, with preimages 11⋅59⋅17911\cdot59\cdot179 and its double), but their primes are large, and up to 10710^7 the device certifies at most r≥19/12r\ge19/12; the sieve of the Problem 417 section, extended for this section, finds no totient up to 10710^7 all of whose preimages are divisible by 66, 1010, 1212, 1515, 2020, 2121, 3535 or 4545, and max⁡v≤107r(v)=2.0414\max_{v\le10^7}r(v)=2.0414. In this range the maximum ratio moves only from 2.03552.0355 to 2.04142.0414 between 10610^6 and 10710^7.

Next investigation. A positive answer needs totients all of whose preimages carry many small prime factors: either the preimages share a divisor kk with many distinct prime factors, the V(x;k)V(x;k) classification, where the witnessed moduli so far have k/φ(k)≤2k/\varphi(k)\le2, or they do not, a structure outside that classification; the finite question whether some totient has all preimages divisible by 66 or by 1010 (Ford's open cases) or by 105105, the least moduli with k/φ(k)>2k/\varphi(k)>2, is the natural first test, and a segmented computation of max⁡r(v)\max r(v) to 10910^9–101010^{10} would show whether max⁡v≤xr(v)\max_{v\le x}r(v) grows with xx at all beyond its value 2.04142.0414 at 10710^7, and in particular whether it reaches 5/25/2 or 33, the ratios a witness for 1010 or 66 would force. A negative answer to Problem 51 (rr bounded by KK) would, through 417.1(a), confine the totients counted by V0(x)V_0(x) to (x/K,x](x/K,x].

Outcome. Fails: no transfer; the shared object yields only the S(k)S(k) cap and a finite-range observation.

Problem 49 and the monotone-set reconstructions: shared inputs

Target. Problem 49: open for the exact clause, whether the primes are a largest subset of [1,N][1,N] with strictly increasing totients; the asymptotic and o(N)o(N) clauses are proved, and Theorem 1.2 of Pollack, Pomerance and Treviño is reconstructed under the Problem 49 folder, whose index records the outcomes for Problems 416 and 417 and points to its connections page and to the lead distinct_totient_preimage_ratio.

What transports. No transfer to the open clause: exact extremality at a finite NN is untouched by counting functions. The relation runs the other way. The folder's W(x)W(x) is Problem 417's V′(x)V'(x) (Maier and Pomerance's V′V' is a third, different count); its Theorem 1.2 reconstruction consumes the same input (W) as the boundedness in Proposition 417.2; and its reversed pair d1=218⋅257<d2=d1+28d_1=2^{18}\cdot257<d_2=d_1+28, with the least preimage of d1d_1 above the largest preimage of d2d_2, has d1d_1 equal to Ford's witness for k=4k=4, an element of the set S(4)S(4) of Theorem 417.3. Lemma 4.1(iii) of that folder, n/φ(n)n/\varphi(n) bounded on Ford's candidate set with two counts imported from Ford's §5, is the route to V≪V′V\ll V' that does not rest on (W) as the cited authors' reading.

Outcome. No transfer; the shared inputs are recorded.

The Problem 49 folder's connections page assesses Problems 416 and 417, reaching the Problem 417 statements independently from Lemma 4.1 and pointing at the lead distinct_totient_preimage_ratio as the single carrier of that route.

Shifted collisions: Problems 1003 and 1004 and the two totient leads

Targets. Problem 1003 (infinitely many nn with φ(n)=φ(n+1)\varphi(n)=\varphi(n+1); open), Problem 1004 (a block of length (log⁡x)c(\log x)^c below xx with pairwise distinct totients, for every cc; open, with the unreviewed candidate totient_blocks_native_note), and Problem 249 (irrationality of ∑φ(n)/2n\sum\varphi(n)/2^n; open, with the editable sketch totient_binary_series).

Why nothing transfers. The write-up's collisions are equalities b(p−1)=b′(p′−1)b(p-1)=b'(p'-1) between two representations of one value; the problems' collisions are equalities φ(n)=φ(n+k)\varphi(n)=\varphi(n+k) between the values at two arguments. A shifted collision between two arguments of pair form, n=m0pn=m_0p and n+k=m0′p′n+k=m_0'p', is a pair collision only when the pairs differ, and (4) counts pair collisions with no rate and no reference to kk, summed over all values up to yy, so it does not bound P(x;k)=#{n≤x:φ(n)=φ(n+k)}P(x;k)=\#\{n\le x:\varphi(n)=\varphi(n+k)\}, which the Problem 1004 page records at x/(log⁡x)2x/(\log x)^2 uniformly for k≤log⁡xk\le\log x from the 2013 manuscript; conversely, pair collisions need not come from arguments at bounded distance, so those bounds do not give (4). Both leads use the values φ(n)\varphi(n) as a sequence indexed by nn (the 22-adic valuations of tail sums for Problem 249, consecutive distinctness for Problem 1004), and the counting function of the value set carries no information about the index. The objects are shared; the mechanism is not.

Outcome. Fails, with the obstruction that representation collisions and argument collisions are different equations.

Other pages checked

  • Value sets of other functions. Problem 418 (integers not of the form n−φ(n)n-\varphi(n); proved) and Problem 822 (positive density of the values of n+φ(n)n+\varphi(n); proved) concern value sets but ask nothing about the regularity of their counting functions, and both are resolved. No erdosproblems.com problem asks for the counting function of the values of σ\sigma, so Ford's Theorem 14, the analogs of Theorems 1–4, 8 and 10–13 for σ\sigma and similar functions, which would carry Proposition 417.2 and the preprint's argument over verbatim, has no consumer here.
  • Problem 48 (common values of φ\varphi and σ\sigma; proved) builds its common values explicitly; Problem 50 (the distribution function of φ(n)/n\varphi(n)/n), Problem 408, Problem 409 and Problem 411 (iterates), Problem 415 (ordering patterns of consecutive values), Problem 456 (the least mm with n∣φ(m)n\mid\varphi(m)), Problem 828 (φ(n)∣n+a\varphi(n)\mid n+a) and Problem 1064 (φ(n)\varphi(n) against φ(n−φ(n))\varphi(n-\varphi(n)); proved) involve φ\varphi at arguments, not the set of its values.
  • Pages where φ\varphi is a notation for something else or enters only as a weight (Problem 220, Problem 971, Problem 999, Problem 787 and the geometric and graph pages the search returned), and the theory claim L16 (kernel separation for the binary series), have no object in common with the mechanisms.