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Source. U. V. Linnik, “On Erdös's theorem on the addition of numerical sequences,” English Sections 2–5, printed pp. 70–77 (PDF pp. 4–11). The preliminary lemmas and the external Vinogradov and large-sieve inputs are on [[integer_sequences/linnik_1942_erdos_theorem_addition_numerical_sequences/lemmas|the preliminary-lemmas page]]. The exact scan is identified in [[integer_sequences/linnik_1942_erdos_theorem_addition_numerical_sequences/_index|the source index]].

The printed result

The paper's main result is unnumbered. Its definition (p. 67): an essential component is a sequence Φ\Phi whose sum with every sequence FF of positive density at least β\beta has density at least β+φ(β)\beta+\varphi(\beta), where φ(β)\varphi(\beta) depends only on β\beta and not on other properties of FF, for β<1\beta<1. A basic sequence is one for which there is an integer a0a_0 such that every natural number is a sum of at most a0a_0 of its terms. The density is Schnirelmann's, as the fourth lemma's hypothesis Ψ(N)≥βN\Psi(N)\geq\beta N shows. After constructing Φ1\Phi_1 and Φ2\Phi_2 (p. 70), the paper states: "We form now the sequence 2Φ1+Φ2=Φ1+Φ1+Φ22\Phi_1+\Phi_2=\Phi_1+\Phi_1+\Phi_2 by ordinary rules and so obtain a sequence Φ\Phi. The sequence Φ\Phi will be a non-basic essential component." (p. 70). Non-basishood is proved in § 2 (pp. 70–71) and the essential-component property in §§ 3–5 (pp. 71–77).

"By ordinary rules" is read here as the addition of sequences in Schnirelmann's theory, where a sum contains its summands. On that reading 1∈Φ1\in\Phi and F⊆F+ΦF\subseteq F+\Phi, which p. 77 uses. This page gives a reconstruction of the same power-set and Fourier argument, with the changes specified below. It writes all sums as Minkowski sums and adjoins {0,1}\{0,1\} explicitly, so the proved component is Φ^\widehat\Phi below.

Statement and addition convention

For F⊆Z>0F\subseteq\mathbb Z_{>0}, write

σ(F)=inf⁡N∈Z≥1∣F∩[1,N]∣N.\sigma(F)=\inf_{N\in\mathbb Z_{\geq1}} \frac{|F\cap[1,N]|}{N}.

There is a fixed set Φ^⊆Z≥0\widehat\Phi\subseteq\mathbb Z_{\geq0}, defined below, which is not an additive basis of any finite order and has the following property. For every 0<β<10<\beta<1 there is φ(β)>0\varphi(\beta)>0 such that, for every F⊆Z>0F\subseteq\mathbb Z_{>0} with σ(F)≥β\sigma(F)\geq\beta and every integer N≥1N\geq1,

∣(F+Φ^)∩[1,N]∣≥(β+φ(β))N.(E)|(F+\widehat\Phi)\cap[1,N]| \geq(\beta+\varphi(\beta))N. \tag{E}

All sums here are ordinary Minkowski sums. Equivalently, one can use the positive sequence Φ^∖{0}\widehat\Phi\setminus\{0\} and explicitly retain FF when adding it. The conclusion is a Schnirelmann-density bound at every cutoff, not just a lower asymptotic-density bound.

This is the essential-component assertion studied by Linnik. It concerns the union of all translates by the component; it does not by itself give the stronger single-shift assertion in Problem 38.

The power sets and the finite augmentation

Use the English construction on p. 70:

c0=exp⁡(1420),N0=⌊exp⁡((log⁡c0)10/9)⌋,Nj=N0 2j(j≥0).c_0=\exp(14^{20}),\qquad N_0=\left\lfloor \exp\bigl((\log c_0)^{10/9}\bigr) \right\rfloor,\qquad N_j=N_0^{\,2^j}\quad(j\geq0).

Put

nj=⌊(log⁡Nj)1/10⌋,Pj=Nj1/nj,dj=⌊nj/2⌋.n_j=\lfloor(\log N_j)^{1/10}\rfloor,\qquad P_j=N_j^{1/n_j},\qquad d_j=\lfloor n_j/2\rfloor.

The starting number is more than sufficient to ensure nj≥3n_j\geq3. Define sets of power values, rather than bounds on their bases:

A0={xn0:x∈Z≥1, 1≤xn0≤N0},A1={xn1:x∈Z≥1, 1≤xn1≤N1},Aj={xnj:x∈Z≥1, Nj−2≤xnj≤Nj}(j≥2).\begin{aligned} A_0&=\{x^{n_0}:x\in\mathbb Z_{\geq1},\ 1\leq x^{n_0}\leq N_0\},\\ A_1&=\{x^{n_1}:x\in\mathbb Z_{\geq1},\ 1\leq x^{n_1}\leq N_1\},\\ A_j&=\{x^{n_j}:x\in\mathbb Z_{\geq1},\ N_{j-2}\leq x^{n_j}\leq N_j\}\quad(j\geq2). \end{aligned}

Let B0,B1,BjB_0,B_1,B_j have the same respective value cutoffs, with degree djd_j in place of njn_j. In particular, the half-degree sets include both B0B_0 and B1B_1.

Set

Φ1=⋃j≥0(A0+A1+⋯+Aj) ∪ ⋃l≥0Al,Φ2=⋃j≥0Bj,\Phi_1=\bigcup_{j\geq0}(A_0+A_1+\cdots+A_j)\ \cup\ \bigcup_{l\geq0}A_l, \qquad \Phi_2=\bigcup_{j\geq0}B_j,

where the j=0j=0 summand in the first union is A0A_0. This spells out the English definition, which takes the prefix sums and also each set AlA_l by itself; p. 70 prints this subscript as an italic ll, not the digit 11. The restriction of Φ1\Phi_1 to [1,Nk][1,N_k] receives no contribution from prefixes ending at j≥k+2j\geq k+2: such a prefix contains a term from Ak+2A_{k+2} at least NkN_k and additional positive terms. Thus it agrees with the cutoff prescription on p. 70. The printed fifth lemma, where Nk−1≤N<NkN_{k-1}\leq N<N_k, places ⌊(βN/40)1/nk⌋nk\lfloor(\beta N/40)^{1/n_k}\rfloor^{n_k} in Φ1\Phi_1 (p. 73); for large NN this power lies in the single set AkA_k.

Finally define

Φ=Φ1+Φ1+Φ2,Φ^={0,1}∪Φ.(C)\Phi=\Phi_1+\Phi_1+\Phi_2, \qquad \widehat\Phi=\{0,1\}\cup\Phi. \tag{C}

The positive sets satisfy 1∈Φ1∩Φ21\in\Phi_1\cap\Phi_2, and the Minkowski sum Φ\Phi has min⁡Φ=3\min\Phi=3, so it does not contain 11, which the paper's convention supplies (p. 77). The finite adjunction in (C) explicitly supplies F⊆F+Φ^F\subseteq F+\widehat\Phi and F+1⊆F+Φ^F+1\subseteq F+\widehat\Phi, as needed in the density argument. It does not change any of the power sets.

Non-basishood, including the degree floors

Let k≥1k\geq1 and put

Rk=∏i=0k(1+Pi).R_k=\prod_{i=0}^{k}(1+P_i).

The total number of choices for prefixes ending at 0,…,k0,\ldots,k is at most RkR_k: their products of cardinalities occur among the nonnegative terms in its expansion. The single sets A0,…,AkA_0,\ldots,A_k contribute at most RkR_k more points, since ∣Ai∣≤Pi|A_i|\leq P_i. A prefix ending at k+1k+1 can use at most Nk1/nk+1≤PkN_k^{1/n_{k+1}}\leq P_k values from its last set, since the degrees are nondecreasing; by the same bound the single set Ak+1A_{k+1} contributes at most PkP_k points. The single set Ak+2A_{k+2} can contribute only the value NkN_k, and later sets contribute nothing. Since Pk+1≤RkP_k+1\leq R_k,

∣Φ1∩[1,Nk]∣≤(Pk+3)Rk.(C1)|\Phi_1\cap[1,N_k]|\leq(P_k+3)R_k. \tag{C1}

For every integer n≥3n\geq3, ⌊n/2⌋≥n/3\lfloor n/2\rfloor\geq n/3. Thus

∣Bi∣≤Ni1/di≤Pi3.|B_i|\leq N_i^{1/d_i}\leq P_i^3.

At cutoff NkN_k, the set Bk+1B_{k+1} contributes at most Nk1/dk≤Pk3N_k^{1/d_k}\leq P_k^3 points. The set Bk+2B_{k+2} can contribute only the value NkN_k, and later sets contribute nothing. Therefore

∣Φ2∩[1,Nk]∣≤1+Pk3+∑i=0kPi3=:Dk.(C2)|\Phi_2\cap[1,N_k]| \leq 1+P_k^3+\sum_{i=0}^{k}P_i^3=:D_k. \tag{C2}

Since all summands in Φ\Phi are positive, (C1) and (C2) give

∣Φ^∩[0,Nk]∣≤2+((Pk+3)Rk)2Dk.(C3)|\widehat\Phi\cap[0,N_k]| \leq2+\bigl((P_k+3)R_k\bigr)^2D_k. \tag{C3}

To estimate this quantity, write Li=log⁡Ni=2iL0L_i=\log N_i=2^iL_0. The floor in nin_i gives ni≥Li1/10/2n_i\geq L_i^{1/10}/2, so

log⁡Pi≤2Li9/10,∑i=0kLi9/10≤Lk9/101−2−9/10.\log P_i\leq2L_i^{9/10},\qquad \sum_{i=0}^{k}L_i^{9/10} \leq\frac{L_k^{9/10}}{1-2^{-9/10}}.

It follows directly from (C1)–(C3) that

log⁡∣Φ^∩[0,Nk]∣=O(Lk9/10+k+log⁡(k+3))=O(Lk9/10).(C4)\log|\widehat\Phi\cap[0,N_k]| =O(L_k^{9/10}+k+\log(k+3)) =O(L_k^{9/10}). \tag{C4}

In particular, ∣Φ^∩[0,Nk]∣=Nko(1)|\widehat\Phi\cap[0,N_k]|=N_k^{o(1)}. For any fixed positive integer hh, every element of hΦ^h\widehat\Phi below NkN_k uses only elements of Φ^∩[0,Nk]\widehat\Phi\cap[0,N_k]. There are at most ∣Φ^∩[0,Nk]∣h=o(Nk)|\widehat\Phi\cap[0,N_k]|^h=o(N_k) ordered choices. Thus hΦ^h\widehat\Phi cannot contain all sufficiently large integers. This also proves non-basishood of the unaugmented Φ\Phi.

The powers Pi3P_i^3 above account for odd nin_i; the printed 2∑Pi22\sum P_i^2 bound does not. The geometric series has sum (1−2−9/10)−1>2(1-2^{-9/10})^{-1}>2, so the printed intermediate constant 3232 on p. 71 also needs replacement. Neither numerical assertion is used here.

Parameters and the power-sum estimates

Fix 0<β<10<\beta<1 for the rest of the proof. Put

β1=1−β2,Dβ=1β1+200ββ1,K=106Dβ.\beta_1=\frac{1-\beta}{2},\qquad D_\beta=\frac1{\beta_1}+\frac{200}{\beta\beta_1}, \qquad K=10^6D_\beta.

We first record precisely which power sums permit the sufficient estimate (W) on the preliminary-lemmas page. Let

pj=⌊Pj⌋,qj=⌈Nj−21/nj⌉−1(j≥2).p_j=\lfloor P_j\rfloor,\qquad q_j=\left\lceil N_{j-2}^{1/n_j}\right\rceil-1\quad(j\geq2).

The bases defining AjA_j are then qj+1,…,pjq_j+1,\ldots,p_j. As j→∞j\to\infty,

nj∼Lj1/10,log⁡pj∼Lj9/10,qjpj⟶0.(P1)n_j\sim L_j^{1/10},\qquad \log p_j\sim L_j^{9/10},\qquad \frac{q_j}{p_j}\longrightarrow0. \tag{P1}

The last limit follows by comparing the logarithms of the lower and upper roots, Lj/(4nj)L_j/(4n_j) and Lj/njL_j/n_j; integer rounding has a vanishing relative effect. Hence eventually

1≤qj≤pj/2,14≤nj≤2(log⁡pj)1/9.(P2)1\leq q_j\leq p_j/2,\qquad 14\leq n_j\leq2(\log p_j)^{1/9}. \tag{P2}

Also, for all sufficiently large jj,

pj<pj+1≤pj nj−1.(P3)p_j<p_{j+1}\leq p_j^{\,n_j-1}. \tag{P3}

Indeed, log⁡pj+1/log⁡pj→29/10>1\log p_{j+1}/\log p_j\to2^{9/10}>1, whereas (nj−1)log⁡pj∼Lj(n_j-1)\log p_j\sim L_j and log⁡pj+1=O(Lj9/10)\log p_{j+1}=O(L_j^{9/10}).

There is a uniform version for the last, truncated sum. If Nr−1≤H<NrN_{r-1}\leq H<N_r and

p=⌊H1/nr⌋,q=⌈Nr−21/nr⌉−1,p=\lfloor H^{1/n_r}\rfloor,\qquad q=\left\lceil N_{r-2}^{1/n_r}\right\rceil-1,

then, uniformly in that range of HH, as r→∞r\to\infty,

1≤q≤p/2,14≤nr≤2(log⁡p)1/9.(P4)1\leq q\leq p/2,\qquad 14\leq n_r\leq2(\log p)^{1/9}. \tag{P4}

For the first assertion, the logarithmic separation of the two roots is at least Lr/(4nr)→∞L_r/(4n_r)\to\infty. For the second, log⁡H≥Lr/2\log H\geq L_r/2 gives nr/(log⁡p)1/9≤21/9+o(1)<2n_r/(\log p)^{1/9}\leq2^{1/9}+o(1)<2. These estimates also show that p→∞p\to\infty uniformly.

Choose j0≥2j_0\geq2 sufficiently large that (P2)–(P3) hold for all j≥j0j\geq j_0, pj0≥P∗p_{j_0}\geq P_*, and

exp⁡(−log⁡pj0)≤1K.\exp\bigl(-\sqrt{\log p_{j_0}}\bigr)\leq\frac1K.

Here P∗P_* is the absolute threshold in (W). Set

b0=pj0,b=⌈10Kb0⌉,δ=ββ11600b.(P5)b_0=p_{j_0},\qquad b=\lceil10Kb_0\rceil,\qquad \delta=\frac{\beta\beta_1}{1600b}. \tag{P5}

These constants depend only on β\beta; bb is an integer greater than one. No predecessor index is needed at the initial crossing.

A large cutoff with too little growth

Let σ(F)≥β\sigma(F)\geq\beta and put F1=F+Φ^F_1=F+\widehat\Phi. We will show that for all sufficiently large integers NN, with a threshold depending only on β\beta,

∣F1∩[1,N]∣≥(β+δ)N.(G)|F_1\cap[1,N]|\geq(\beta+\delta)N. \tag{G}

Suppose to the contrary that the reverse strict inequality holds. Since δ<β1\delta<\beta_1, the complement of F1F_1 below NN has more than β1N\beta_1N points. Let

MN={m∈[1,N]∩Z:m∉F1, m≥β1N/2},Z1=∣MN∣.\mathcal M_N= \{m\in[1,N]\cap\mathbb Z:m\notin F_1,\ m\geq\beta_1N/2\}, \qquad Z_1=|\mathcal M_N|.

Fewer than β1N/2\beta_1N/2 positive integers lie below β1N/2\beta_1N/2. Therefore

Z1>β1N2.(G1)Z_1>\frac{\beta_1N}{2}. \tag{G1}

Take the smaller cutoff

H=⌊β1N100⌋.(G2)H=\left\lfloor\frac{\beta_1N}{100}\right\rfloor. \tag{G2}

For sufficiently large NN, H≥β1N/200H\geq\beta_1N/200 and H>4b/βH>4b/\beta. Apply the corrected fourth lemma at HH, with C=bC=b and ε=β/2\varepsilon=\beta/2. Its first alternative would give

∣(F∪(F+1))∩[1,H]∣−∣F∩[1,H]∣≥βH4b≥ββ1N800b=2δN.|(F\cup(F+1))\cap[1,H]|-|F\cap[1,H]| \geq\frac{\beta H}{4b} \geq\frac{\beta\beta_1N}{800b}=2\delta N.

All these new points belong to F1F_1, and F⊆F1F\subseteq F_1. This would contradict ∣F1∩[1,N]∣<(β+δ)N|F_1\cap[1,N]|<(\beta+\delta)N.

Consequently the set

GN={f∈F∩[1,H]:{f,f+1,…,f+b}⊆F∩[1,H]}\mathcal G_N= \{f\in F\cap[1,H]:\{f,f+1,\ldots,f+b\}\subseteq F\cap[1,H]\}

has cardinality

Z2=∣GN∣>βH2≥ββ1N400.(G3)Z_2=|\mathcal G_N|>\frac{\beta H}{2} \geq\frac{\beta\beta_1N}{400}. \tag{G3}

This directly counts good starts at the cutoff where they are used; it does not discard an uncontrolled second half of an interval.

Choose the unique kk with Nk−1≤N<NkN_{k-1}\leq N<N_k, and put

X1=⌊N1−11/(10nk)⌋.(G4)X_1=\left\lfloor N^{1-11/(10n_k)}\right\rfloor. \tag{G4}

For sufficiently large NN,

N3/4<X1<N(log⁡N)2.N^{3/4}<X_1<\frac{N}{(\log N)^2}.

Here nk→∞n_k\to\infty, while (log⁡N)/nk(\log N)/n_k grows on the order of (log⁡N)9/10(\log N)^{9/10}, faster than log⁡log⁡N\log\log N. These facts justify both inequalities, including the floor. Apply the difference form of the third lemma to MN,GN⊆[1,N]\mathcal M_N,\mathcal G_N\subseteq[1,N], with γ0=ββ1/800\gamma_0=\beta\beta_1/800. We obtain a prime p∈[X1/2,X1]p\in[X_1/2,X_1] such that every residue vv satisfies

#{(m,f)∈MN×GN:m−f≡v(modp)}≥crepZ1Z2p,crep=0.99616.(G5)\#\{(m,f)\in\mathcal M_N\times\mathcal G_N: m-f\equiv v\pmod p\} \geq c_{\mathrm{rep}}\frac{Z_1Z_2}{p}, \qquad c_{\mathrm{rep}}=\frac{0.996}{16}. \tag{G5}

Fifth lemma: an interval in the difference set

Define

DN=(MN−(F∩[1,N])−(Φ1∩[1,N])−(Φ1∩[1,N]))∩[1,N].\mathcal D_N= \bigl(\mathcal M_N-(F\cap[1,N]) -(\Phi_1\cap[1,N])-(\Phi_1\cap[1,N])\bigr)\cap[1,N].

For all sufficiently large NN under the preceding supposition, DN\mathcal D_N contains all integers in an interval [Y1,Y2][Y_1,Y_2] with

1≤Y1<Y2≤N,Y2−Y1≥X1/4.(L)1\leq Y_1<Y_2\leq N,\qquad Y_2-Y_1\geq X_1/4. \tag{L}

This is the form of Linnik's fifth lemma required below. We prove it with explicit supports and cardinalities.

Omitted values and the comparison sum

Suppose (L) fails, and let s=⌈X1/4⌉s=\lceil X_1/4\rceil and w=⌊N/p⌋w=\lfloor N/p\rfloor. Every interval of s+1s+1 consecutive integers inside [1,N][1,N] then has a value omitted by DN\mathcal D_N. For j=1,…,wj=1,\ldots,w, choose one such omitted value

wj∈[jp−s,jp]∖DN.w_j\in[jp-s,jp]\setminus\mathcal D_N.

When X1≥8X_1\geq8, these intervals lie in [1,N][1,N] and are disjoint: s+1≤ps+1\leq p. In particular, the wjw_j are distinct and

0≤jp−wj≤s.(L1)0\leq jp-w_j\leq s. \tag{L1}

Let rr be determined by Nr−1≤H<NrN_{r-1}\leq H<N_r. For NN sufficiently large we have r>j0r>j_0. Take

S1(α)=∑m∈MNe(αm),S2(α)=∑f∈GNe(−αf),U(α)=∑u=0be(−αu),Tj(α)=∑t∈Aje(−αt)(0≤j<r),Tr(α)=∑x∈Z≥1Nr−2≤xnr≤He(−αxnr),W(α)=∑j=1we(−αwj),Q(α)=∑x=0we(−αpx).\begin{aligned} S_1(\alpha)&=\sum_{m\in\mathcal M_N}e(\alpha m),& S_2(\alpha)&=\sum_{f\in\mathcal G_N}e(-\alpha f),\\ U(\alpha)&=\sum_{u=0}^{b}e(-\alpha u),& T_j(\alpha)&=\sum_{t\in A_j}e(-\alpha t)\quad(0\leq j<r),\\ T_r(\alpha)&=\sum_{\substack{x\in\mathbb Z_{\geq1}\\ N_{r-2}\leq x^{n_r}\leq H}}e(-\alpha x^{n_r}),& W(\alpha)&=\sum_{j=1}^{w}e(-\alpha w_j),\\ Q(\alpha)&=\sum_{x=0}^{w}e(-\alpha px).&& \end{aligned}

Write

R(α)=U(α)∏j=0rTj(α),A=R(0)=(b+1)∏j=0rTj(0).R(\alpha)=U(\alpha)\prod_{j=0}^{r}T_j(\alpha), \qquad A=R(0)=(b+1)\prod_{j=0}^{r}T_j(0).

All the power sums are nonempty for these large cutoffs. A selection of their terms has sum

ϕ=t0+⋯+tr∈A0+⋯+Ar⊆Φ1.\phi=t_0+\cdots+t_r\in A_0+\cdots+A_r\subseteq\Phi_1.

Since Ni+1=Ni2N_{i+1}=N_i^2 and N0≥2N_0\geq2,

ϕ≤∑j=0r−1Nj+H≤2Nr−1+H≤3H.(L2)\phi\leq\sum_{j=0}^{r-1}N_j+H \leq2N_{r-1}+H\leq3H. \tag{L2}

This is the truncation needed in the counting argument.

Use the fixed value M=1∈Φ1M=1\in\Phi_1 and consider

I=∫01S1S2RW e(−α) dα,J=∫01S1S2RQ e(−α) dα.(L3)I=\int_0^1 S_1S_2RW\,e(-\alpha)\,d\alpha, \qquad J=\int_0^1 S_1S_2RQ\,e(-\alpha)\,d\alpha. \tag{L3}

Orthogonality shows that II counts the ordered choices satisfying

wj=m−(f+u)−ϕ−1.w_j=m-(f+u)-\phi-1.

Here f+u∈F∩[1,H]f+u\in F\cap[1,H], ϕ∈Φ1∩[1,N]\phi\in\Phi_1\cap[1,N], and 1∈Φ1∩[1,N]1\in\Phi_1\cap[1,N]. Thus any counted wjw_j would belong to DN\mathcal D_N, contrary to its selection. Hence I=0I=0.

For JJ, fix u,t0,…,tru,t_0,\ldots,t_r. Every pair (m,f)(m,f) satisfying the appropriate congruence from (G5) gives

m−(f+u)−ϕ−1=px.(L4)m-(f+u)-\phi-1=px. \tag{L4}

Indeed, the left side is an integer between 00 and NN: its lower bound is

β1N2−4H−1>0\frac{\beta_1N}{2}-4H-1>0

for sufficiently large NN, by (G2) and (L2), while its upper bound is at most m≤Nm\leq N. Therefore its quotient by pp is one of 0,…,w0,\ldots,w. This proves the lower bound

J≥crepZ1Z2pA.(L5)J\geq c_{\mathrm{rep}}\frac{Z_1Z_2}{p}A. \tag{L5}

Denominator coverage and the minor arcs

Put

P=⌊H1/nr⌋,τ=Pnr−1.P=\lfloor H^{1/n_r}\rfloor,\qquad \tau=P^{n_r-1}.

Both are integers. In view of (P4), the sufficient estimate (W) applies to TrT_r for denominators in [P,τ][P,\tau]. It applies to TjT_j, j0≤j<rj_0\leq j<r, for denominators in [pj,pjnj−1][p_j,p_j^{n_j-1}]. Take NN large enough that P≥b0P\geq b_0 and that all the truncated conditions (P4) hold. Each applicable estimate then bounds its factor by at most its cardinality divided by KK.

By (P3), the intervals [pj,pjnj−1][p_j,p_j^{n_j-1}] overlap successively. Moreover,

P≤pr≤pr−1nr−1−1.P\leq p_r\leq p_{r-1}^{n_{r-1}-1}.

The last interval [P,τ][P,\tau] therefore overlaps that chain. Every denominator in [b0,τ][b_0,\tau] is covered by at least one of these power sums. The initial factors with j<j0j<j_0 require only their trivial cardinality bounds.

Dirichlet's approximation theorem, with the integer cutoff τ\tau, gives, for every α∈R/Z\alpha\in\mathbb R/\mathbb Z, coprime integers a,qa,q with

1≤q≤τ,∣α−aq∣≤1qτ.(L6)1\leq q\leq\tau,\qquad \left|\alpha-\frac aq\right|\leq\frac1{q\tau}. \tag{L6}

For the minor arcs ∥α∥>2/τ\|\alpha\|>2/\tau, where ∥α∥\|\alpha\| denotes distance to the nearest integer, this cannot have q=1q=1. If q≥b0q\geq b_0, the preceding denominator coverage gives cancellation in one power sum; (L6) also implies the required error at most 1/q21/q^2.

If 2≤q<b02\leq q<b_0, then for τ≥2\tau\geq2,

∥α∥≥1q−1qτ≥12q.\|\alpha\|\geq\frac1q-\frac1{q\tau}\geq\frac1{2q}.

The geometric-sum estimate gives

∣U(α)∣≤12∥α∥≤q<b0≤b+110K.|U(\alpha)|\leq\frac1{2\|\alpha\|}\leq q<b_0 \leq\frac{b+1}{10K}.

Thus in all cases

∣R(α)∣≤A/K(∥α∥>2/τ).(L7)|R(\alpha)|\leq A/K \qquad(\|\alpha\|>2/\tau). \tag{L7}

Parseval and the arithmetic-geometric mean inequality give

∫01∣S1S2∣ dα≤Z1+Z22=Z1Z22(1Z1+1Z2)≤DβZ1Z2N,(L8)\begin{aligned} \int_0^1|S_1S_2|\,d\alpha &\leq\frac{Z_1+Z_2}{2}\\ &=\frac{Z_1Z_2}{2}\left(\frac1{Z_1}+\frac1{Z_2}\right) \leq D_\beta\frac{Z_1Z_2}{N}, \end{aligned} \tag{L8}

using (G1) and (G3). Since ∣W∣≤w|W|\leq w and ∣Q∣≤w+1≤2w|Q|\leq w+1\leq2w, the absolute values of the minor-arc parts of II and JJ are at most, respectively,

DβKAZ1Z2wN,2DβKAZ1Z2wN.(L9)\frac{D_\beta}{K}\frac{AZ_1Z_2w}{N}, \qquad \frac{2D_\beta}{K}\frac{AZ_1Z_2w}{N}. \tag{L9}

The major arcs and the distinct scales

The needed major-arc approximation follows from X1/τ→0X_1/\tau\to0. Here the definitions of X1X_1 and τ\tau use different cutoffs and possibly different degree indices; they are not equated.

For fixed β\beta, (G2) implies H=(β1/100)N+O(1)H=(\beta_1/100)N+O(1). Eventually H≥Nk−2H\geq N_{k-2}, because N≥Nk−1=Nk−22N\geq N_{k-1}=N_{k-2}^2. Since H<N<NkH<N<N_k, this gives r∈{k−1,k}r\in\{k-1,k\}. The degree floors satisfy

nknr≤1.08\frac{n_k}{n_r}\leq1.08

for all sufficiently large kk, because the only nontrivial limiting ratio is 21/10<1.082^{1/10}<1.08. Integer root rounding gives

log⁡τ=(1−1/nr)log⁡H+o(1).\log\tau=(1-1/n_r)\log H+o(1).

Combining this with (G4),

log⁡(X1/τ)=(1nr−1.1nk)log⁡N−(1−1/nr)log⁡(β1/100)+o(1)≤−log⁡N50nk+Oβ(1)⟶−∞.(L10)\begin{aligned} \log(X_1/\tau) &=\left(\frac1{n_r}-\frac{1.1}{n_k}\right)\log N -(1-1/n_r)\log(\beta_1/100)+o(1)\\ &\leq-\frac{\log N}{50n_k}+O_\beta(1) \longrightarrow-\infty. \end{aligned} \tag{L10}

Also w≥⌊N/X1⌋→∞w\geq\lfloor N/X_1\rfloor\to\infty. On ∥α∥≤2/τ\|\alpha\|\leq2/\tau, pair the terms of WW with the nonconstant terms of QQ. By (L1),

∣Q(α)−W(α)∣≤1+4πwsτ≤wK(L11)|Q(\alpha)-W(\alpha)| \leq1+\frac{4\pi ws}{\tau}\leq\frac wK \tag{L11}

for all sufficiently large NN. Indeed, 1/w+4πs/τ→01/w+4\pi s/\tau\to0 uniformly for primes p∈[X1/2,X1]p\in[X_1/2,X_1].

Using the trivial bound ∣R∣≤A|R|\leq A and (L8), the major-arc contribution to J−IJ-I is at most

DβKAZ1Z2wN.\frac{D_\beta}{K}\frac{AZ_1Z_2w}{N}.

Together with (L9), this gives

∣J−I∣≤4DβKAZ1Z2wN.(L12)|J-I|\leq\frac{4D_\beta}{K}\frac{AZ_1Z_2w}{N}. \tag{L12}

But 1/p≥w/N1/p\geq w/N, so (L5) and (L12) imply

I≥(crep−4DβK)AZ1Z2wN>0.I\geq \left(c_{\mathrm{rep}}-\frac{4D_\beta}{K}\right) \frac{AZ_1Z_2w}{N}>0.

Here crep=0.996/16c_{\mathrm{rep}}=0.996/16 and 4Dβ/K=4⋅10−64D_\beta/K=4\cdot10^{-6}. This contradicts I=0I=0, proving (L).

Half-degree powers meet the interval

We justify the power-gap assertion including transitions between blocks. For a real z∈[Nj−1,Nj)z\in[N_{j-1},N_j) with j≥2j\geq2, put

bz=⌊z1/dj⌋dj.b_z=\lfloor z^{1/d_j}\rfloor^{d_j}.

For all sufficiently large jj, uniformly in this range of zz, bz≥z/2≥Nj−2b_z\geq z/2\geq N_{j-2}. To see the first inequality, write x=z1/djx=z^{1/d_j} and use

bzz≥(1−1/x)dj≥1−djx≥12.\frac{b_z}{z}\geq(1-1/x)^{d_j}\geq1-\frac{d_j}{x}\geq\frac12.

The last inequality holds uniformly since x≥Nj−11/djx\geq N_{j-1}^{1/d_j} grows faster than djd_j. The second follows from Nj−1=Nj−22N_{j-1}=N_{j-2}^2 and Nj−2≥2N_{j-2}\geq2. Thus bz∈Bj⊆Φ2b_z\in B_j\subseteq\Phi_2. The mean value theorem also gives

0≤z−bz≤djz1−1/dj.(H1)0\leq z-b_z\leq d_jz^{1-1/d_j}. \tag{H1}

When 1≤z≤N1\leq z\leq N and Nk−1≤N<NkN_{k-1}\leq N<N_k, the relevant index jj is at most kk. The degrees djd_j are nondecreasing. Hence the right side of (H1) is at most

ΔN=dkN1−1/dk.\Delta_N=d_kN^{1-1/d_k}.

The finitely many initial ranges not covered by the uniform argument are contained in some fixed [1,N∗][1,N_*]. They can use 1∈B01\in B_0 as the preceding element; for large NN, ΔN≥N∗\Delta_N\geq N_*. We have therefore proved that, for every z∈[1,N]z\in[1,N], some bz∈Φ2b_z\in\Phi_2 satisfies z−ΔN≤bz≤zz-\Delta_N\leq b_z\leq z. This argument chooses a power in a valid overlapping block at each cutoff; it does not assume that adjacent blocks have matching endpoints.

Since dk=⌊nk/2⌋≤nk/2d_k=\lfloor n_k/2\rfloor\leq n_k/2, (G4) yields

ΔNX1≤(1+o(1))dkexp⁡(−0.9log⁡Nnk)⟶0.(H2)\frac{\Delta_N}{X_1} \leq(1+o(1))d_k \exp\left(-\frac{0.9\log N}{n_k}\right) \longrightarrow0. \tag{H2}

For large NN, apply this preceding-power assertion to the upper endpoint Y2Y_2 in (L). As ΔN<X1/4≤Y2−Y1\Delta_N<X_1/4\leq Y_2-Y_1, it supplies ϕ2∈Φ2∩[Y1,Y2]\phi_2\in\Phi_2\cap[Y_1,Y_2]. By the definition of DN\mathcal D_N,

ϕ2=m−f−ϕ1−ϕ1′\phi_2=m-f-\phi_1-\phi'_1

for some m∈MNm\in\mathcal M_N, f∈Ff\in F, and ϕ1,ϕ1′∈Φ1\phi_1,\phi'_1\in\Phi_1. Consequently

m=f+ϕ1+ϕ1′+ϕ2∈F+Φ⊆F1,m=f+\phi_1+\phi'_1+\phi_2\in F+\Phi\subseteq F_1,

contrary to m∈MNm\in\mathcal M_N. This proves (G).

Every cutoff and the density increment

All thresholds above depend only on β\beta: the fourth lemma uses b,βb,\beta, the prime-selection lemma uses γ0=ββ1/800\gamma_0=\beta\beta_1/800, and the remaining conditions follow from the displayed uniform limits and the fixed power construction. Choose an integer Nβ≥1N_\beta\geq1 beyond all of them. Then (G) holds for every N>NβN>N_\beta and every FF with σ(F)≥β\sigma(F)\geq\beta.

For 1≤N≤Nβ1\leq N\leq N_\beta, positive Schnirelmann density implies 1∈F1\in F. If FF omits a point of [1,N][1,N], its first omitted point has a predecessor in FF, so it belongs to F+1F+1. Since {0,1}⊆Φ^\{0,1\}\subseteq\widehat\Phi,

∣F1∩[1,N]∣≥∣F∩[1,N]∣+1≥βN+1.|F_1\cap[1,N]|\geq|F\cap[1,N]|+1\geq\beta N+1.

If no point is omitted, the count is NN. Set

φ(β)=min⁡{δ,1Nβ,1−β}>0.\varphi(\beta)= \min\left\{\delta,\frac1{N_\beta},1-\beta\right\}>0.

The two small-cutoff cases and (G) prove (E) for every positive integer NN. Together with (C4), this proves the asserted non-basic essential-component construction. □\square

Relation to the printed proof

The reconstruction retains the English power sets, the prime-selection lemma, the omitted-value comparison, Weyl cancellation on overlapping denominator ranges, and the half-degree covering argument. The following changes are substantive bookkeeping corrections, not identities asserted by the scan.

  • Pp. 67, 70 and 77: addition. The paper adds sequences "by ordinary rules", read here as Schnirelmann's addition, which keeps the summands and so gives 1∈Φ1\in\Phi and F⊆F+ΦF\subseteq F+\Phi (p. 77). Minkowski sums of the positive sets give min⁡Φ=3\min\Phi=3, so the stated theorem adjoins {0,1}\{0,1\} explicitly as Φ^\widehat\Phi.
  • P. 70: construction. The cutoffs bound the powers, and all the half-degree blocks start at B0B_0. The English prefix union is retained exactly. Bounds on the bases and omission of B0,B1B_0,B_1 were errors in the earlier compilation, not in this source definition.
  • Pp. 68–70: preliminary estimates. The normalized Weyl estimate used here is the proved sufficient specialization (W); the full printed first-lemma parameter range is not certified here. The fourth lemma needs its terminal boundary and a threshold depending on ε\varepsilon, as proved on the preliminary-lemmas page.
  • P. 71: counts and initial index. Odd degrees require a count such as Pi3P_i^3, and the geometric series cannot be bounded by two. The second printed crossing inequality uses Pk0−1P_{k_0-1}, not log⁡Pk0−1\sqrt{\log P_{k_0}}-1. Choosing a sufficiently large j0≥2j_0\geq2 avoids an undefined predecessor and supplies all needed estimates.
  • P. 72: retained mass. The printed second truncation of good starts does not justify its asserted Z2Z_2 bound. Here the corrected fourth lemma is applied directly at HH and yields (G3). Also Z1Z_1 counts the restricted set MN\mathcal M_N, not the whole complement.
  • Pp. 72–76: the two scales. The source uses X1=N1−1.1/nkX_1=N^{1-1.1/n_k} and later τ=(β1N/10)1−1/nk\tau=(\beta_1N/10)^{1-1/n_k}. Its fifth-lemma display on p. 72 has an inconsistent factor 1/21/2 versus 1/41/4; Section 5 uses the latter. Here integer X1X_1 retains the source's NN scale, while τ\tau belongs to the explicitly truncated HH scale. Equation (L10) proves the comparison actually needed.
  • Pp. 73–74: signs, membership and positivity. The printed S2S_2 has the wrong sign for the equation it is said to count; the negative sign is used here. As printed, the omitted values already lie outside the difference set: the overlined ∈\in on p. 73 denotes non-membership. The product includes T0T_0, so its sums lie in the stated prefix union. The fixed value M=1∈Φ1M=1\in\Phi_1 replaces the printed power at the βN/40\beta N/40 scale. Full lower blocks and a final block truncated at HH satisfy (L2), which proves (L4). The source's displayed supports up to NN do not imply its claimed positivity for every choice.
  • Pp. 76–77: half-degree gaps. The printed exponent on p. 77 is 1−1/nk′1-1/n'_k, with nk′=⌊nk/2⌋n'_k=\lfloor n_k/2\rfloor. Dropping that prime was a compilation error. Equations (H1)–(H2) supply the floor and block-transition details omitted in the short source argument.
  • P. 78: Russian summary. It prints the smaller starting value ⌊exp⁡(1420)⌋\lfloor\exp(14^{20})\rfloor and a compressed description of Φ1\Phi_1 differing from the English prefix union. Those formulas are not mixed into the English proof.

Bears on. Problem 38: the result gives a set that is not a basis of any finite order whose sum with every set of Schnirelmann density at least β∈(0,1)\beta\in(0,1) gains a fixed φ(β)>0\varphi(\beta)>0 in density at every cutoff. The sum uses all elements of the set at once, whereas Problem 38 asks that for every AA and every cutoff NN a single element bb give A∪(A+b)A\cup(A+b) the gain up to NN, so the result does not by itself answer the problem.