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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 whose sum with every sequence
F of positive density at least β has density at least
β+φ(β), where φ(β) depends only on
β and not on other properties of F, for β<1. A basic
sequence is one for which there is an integer a0 such that every
natural number is a sum of at most a0 of its terms. The density is
Schnirelmann's, as the fourth lemma's hypothesis Ψ(N)≥βN
shows. After constructing Φ1 and Φ2 (p. 70), the paper states:
"We form now the sequence 2Φ1+Φ2=Φ1+Φ1+Φ2 by
ordinary rules and so obtain a sequence Φ. The sequence Φ 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∈Φ and F⊆F+Φ, 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} explicitly, so the proved component is Φ below.
Statement and addition convention
For F⊆Z>0, write
σ(F)=N∈Z≥1infN∣F∩[1,N]∣.
There is a fixed set Φ⊆Z≥0, defined
below, which is not an additive basis of any finite order and has the
following property. For every 0<β<1 there is φ(β)>0
such that, for every F⊆Z>0 with σ(F)≥β
and every integer N≥1,
∣(F+Φ)∩[1,N]∣≥(β+φ(β))N.(E)
All sums here are ordinary Minkowski sums. Equivalently, one can use the
positive sequence Φ∖{0} and explicitly retain F
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.
Let B0,B1,Bj have the same respective value cutoffs, with degree
dj in place of nj. In particular, the half-degree sets include
both B0 and B1.
Set
Φ1=j≥0⋃(A0+A1+⋯+Aj)∪l≥0⋃Al,Φ2=j≥0⋃Bj,
where the j=0 summand in the first union is A0. This spells out the
English definition, which takes the prefix sums and also each set Al
by itself; p. 70 prints this subscript as an italic l, not the digit
1. The restriction of Φ1 to [1,Nk] receives no contribution
from prefixes ending at j≥k+2: such a prefix contains a term from
Ak+2 at least Nk and additional positive terms. Thus it agrees
with the cutoff prescription on p. 70. The printed fifth lemma, where
Nk−1≤N<Nk, places ⌊(βN/40)1/nk⌋nk
in Φ1 (p. 73); for large N this power lies in the single set
Ak.
Finally define
Φ=Φ1+Φ1+Φ2,Φ={0,1}∪Φ.(C)
The positive sets satisfy 1∈Φ1∩Φ2, and the Minkowski
sum Φ has minΦ=3, so it does not contain 1, which the
paper's convention supplies (p. 77). The finite adjunction in (C) explicitly
supplies F⊆F+Φ and
F+1⊆F+Φ, as needed in the density argument.
It does not change any of the power sets.
Non-basishood, including the degree floors
Let k≥1 and put
Rk=i=0∏k(1+Pi).
The total number of choices for prefixes ending at 0,…,k is at
most Rk: their products of cardinalities occur among the nonnegative
terms in its expansion. The single sets A0,…,Ak contribute at
most Rk more points, since ∣Ai∣≤Pi. A prefix ending at k+1
can use at most Nk1/nk+1≤Pk values from its last set, since
the degrees are nondecreasing; by the same bound the single set Ak+1
contributes at most Pk points. The single set Ak+2 can contribute
only the value Nk, and later sets contribute nothing. Since
Pk+1≤Rk,
∣Φ1∩[1,Nk]∣≤(Pk+3)Rk.(C1)
For every integer n≥3, ⌊n/2⌋≥n/3. Thus
∣Bi∣≤Ni1/di≤Pi3.
At cutoff Nk, the set Bk+1 contributes at most
Nk1/dk≤Pk3 points. The set Bk+2 can contribute only
the value Nk, and later sets contribute nothing. Therefore
∣Φ2∩[1,Nk]∣≤1+Pk3+i=0∑kPi3=:Dk.(C2)
Since all summands in Φ are positive, (C1) and (C2) give
∣Φ∩[0,Nk]∣≤2+((Pk+3)Rk)2Dk.(C3)
To estimate this quantity, write Li=logNi=2iL0. The floor in
ni gives ni≥Li1/10/2, so
In particular, ∣Φ∩[0,Nk]∣=Nko(1). For any fixed
positive integer h, every element of hΦ below Nk uses
only elements of Φ∩[0,Nk]. There are at most
∣Φ∩[0,Nk]∣h=o(Nk) ordered choices. Thus
hΦ cannot contain all sufficiently large integers.
This also proves non-basishood of the unaugmented Φ.
The powers Pi3 above account for odd ni; the printed
2∑Pi2 bound does not. The geometric series has sum
(1−2−9/10)−1>2, so the printed intermediate constant 32 on
p. 71 also needs replacement. Neither numerical assertion is used here.
Parameters and the power-sum estimates
Fix 0<β<1 for the rest of the proof. Put
β1=21−β,Dβ=β11+ββ1200,K=106Dβ.
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).
The bases defining Aj are then qj+1,…,pj.
As j→∞,
nj∼Lj1/10,logpj∼Lj9/10,pjqj⟶0.(P1)
The last limit follows by comparing the logarithms of the lower and upper
roots, Lj/(4nj) and Lj/nj; integer rounding has a vanishing
relative effect. Hence eventually
1≤qj≤pj/2,14≤nj≤2(logpj)1/9.(P2)
Also, for all sufficiently large j,
pj<pj+1≤pjnj−1.(P3)
Indeed, logpj+1/logpj→29/10>1, whereas
(nj−1)logpj∼Lj and
logpj+1=O(Lj9/10).
There is a uniform version for the last, truncated sum. If
Nr−1≤H<Nr and
p=⌊H1/nr⌋,q=⌈Nr−21/nr⌉−1,
then, uniformly in that range of H, as r→∞,
1≤q≤p/2,14≤nr≤2(logp)1/9.(P4)
For the first assertion, the logarithmic separation of the two roots is
at least Lr/(4nr)→∞. For the second,
logH≥Lr/2 gives
nr/(logp)1/9≤21/9+o(1)<2. These estimates also show
that p→∞ uniformly.
Choose j0≥2 sufficiently large that (P2)–(P3) hold for all
j≥j0, pj0≥P∗, and
exp(−logpj0)≤K1.
Here P∗ is the absolute threshold in (W). Set
b0=pj0,b=⌈10Kb0⌉,δ=1600bββ1.(P5)
These constants depend only on β; b 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 and put F1=F+Φ. We will show that
for all sufficiently large integers N, with a threshold depending only
on β,
∣F1∩[1,N]∣≥(β+δ)N.(G)
Suppose to the contrary that the reverse strict inequality holds. Since
δ<β1, the complement of F1 below N has more than
β1N points. Let
MN={m∈[1,N]∩Z:m∈/F1,m≥β1N/2},Z1=∣MN∣.
Fewer than β1N/2 positive integers lie below β1N/2.
Therefore
Z1>2β1N.(G1)
Take the smaller cutoff
H=⌊100β1N⌋.(G2)
For sufficiently large N, H≥β1N/200 and
H>4b/β. Apply the corrected fourth lemma at H, with C=b
and ε=β/2. Its first alternative would give
∣(F∪(F+1))∩[1,H]∣−∣F∩[1,H]∣≥4bβH≥800bββ1N=2δN.
All these new points belong to F1, and F⊆F1. This would
contradict ∣F1∩[1,N]∣<(β+δ)N.
Consequently the set
GN={f∈F∩[1,H]:{f,f+1,…,f+b}⊆F∩[1,H]}
has cardinality
Z2=∣GN∣>2βH≥400ββ1N.(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 k with Nk−1≤N<Nk, and put
X1=⌊N1−11/(10nk)⌋.(G4)
For sufficiently large N,
N3/4<X1<(logN)2N.
Here nk→∞, while
(logN)/nk grows on the order of (logN)9/10, faster than
loglogN. These facts justify both inequalities, including the floor.
Apply the difference form of the third lemma to
MN,GN⊆[1,N], with
γ0=ββ1/800. We obtain a prime
p∈[X1/2,X1] such that every residue v satisfies
For all sufficiently large N under the preceding supposition,
DN contains all integers in an interval [Y1,Y2] with
1≤Y1<Y2≤N,Y2−Y1≥X1/4.(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⌉ and
w=⌊N/p⌋. Every interval of s+1 consecutive integers
inside [1,N] then has a value omitted by DN. For
j=1,…,w, choose one such omitted value
wj∈[jp−s,jp]∖DN.
When X1≥8, these intervals lie in [1,N] and are disjoint:
s+1≤p. In particular, the wj are distinct and
0≤jp−wj≤s.(L1)
Let r be determined by Nr−1≤H<Nr. For N sufficiently
large we have r>j0. Take
All the power sums are nonempty for these large cutoffs. A selection of
their terms has sum
ϕ=t0+⋯+tr∈A0+⋯+Ar⊆Φ1.
Since Ni+1=Ni2 and N0≥2,
ϕ≤j=0∑r−1Nj+H≤2Nr−1+H≤3H.(L2)
This is the truncation needed in the counting argument.
Use the fixed value M=1∈Φ1 and consider
I=∫01S1S2RWe(−α)dα,J=∫01S1S2RQe(−α)dα.(L3)
Orthogonality shows that I counts the ordered choices satisfying
wj=m−(f+u)−ϕ−1.
Here f+u∈F∩[1,H], ϕ∈Φ1∩[1,N], and
1∈Φ1∩[1,N]. Thus any counted wj would belong to
DN, contrary to its selection. Hence I=0.
For J, fix u,t0,…,tr. Every pair (m,f) satisfying the
appropriate congruence from (G5) gives
m−(f+u)−ϕ−1=px.(L4)
Indeed, the left side is an integer between 0 and N: its lower
bound is
2β1N−4H−1>0
for sufficiently large N, by (G2) and (L2), while its upper bound
is at most m≤N. Therefore its quotient by p is one of
0,…,w. This proves the lower bound
J≥creppZ1Z2A.(L5)
Denominator coverage and the minor arcs
Put
P=⌊H1/nr⌋,τ=Pnr−1.
Both are integers. In view of (P4), the sufficient estimate (W) applies
to Tr for denominators in [P,τ]. It applies to Tj,
j0≤j<r, for denominators in [pj,pjnj−1].
Take N large enough that P≥b0 and that all the truncated
conditions (P4) hold. Each applicable estimate then bounds its factor
by at most its cardinality divided by K.
By (P3), the intervals [pj,pjnj−1] overlap successively.
Moreover,
P≤pr≤pr−1nr−1−1.
The last interval [P,τ] therefore overlaps that chain. Every
denominator in [b0,τ] is covered by at least one of these power
sums. The initial factors with j<j0 require only their trivial
cardinality bounds.
Dirichlet's approximation theorem, with the integer cutoff τ,
gives, for every α∈R/Z, coprime integers
a,q with
1≤q≤τ,α−qa≤qτ1.(L6)
For the minor arcs ∥α∥>2/τ, where ∥α∥ denotes
distance to the nearest integer, this cannot have q=1. If q≥b0,
the preceding denominator coverage gives cancellation in one power sum;
(L6) also implies the required error at most 1/q2.
If 2≤q<b0, then for τ≥2,
∥α∥≥q1−qτ1≥2q1.
The geometric-sum estimate gives
∣U(α)∣≤2∥α∥1≤q<b0≤10Kb+1.
Thus in all cases
∣R(α)∣≤A/K(∥α∥>2/τ).(L7)
Parseval and the arithmetic-geometric mean inequality give
using (G1) and (G3). Since ∣W∣≤w and ∣Q∣≤w+1≤2w,
the absolute values of the minor-arc parts of I and J are at most,
respectively,
KDβNAZ1Z2w,K2DβNAZ1Z2w.(L9)
The major arcs and the distinct scales
The needed major-arc approximation follows from X1/τ→0.
Here the definitions of X1 and τ use different cutoffs and
possibly different degree indices; they are not equated.
For fixed β, (G2) implies
H=(β1/100)N+O(1). Eventually H≥Nk−2, because
N≥Nk−1=Nk−22. Since H<N<Nk, this gives
r∈{k−1,k}. The degree floors satisfy
nrnk≤1.08
for all sufficiently large k, because the only nontrivial limiting
ratio is 21/10<1.08. Integer root rounding gives
Also w≥⌊N/X1⌋→∞. On
∥α∥≤2/τ, pair the terms of W with the nonconstant
terms of Q. By (L1),
∣Q(α)−W(α)∣≤1+τ4πws≤Kw(L11)
for all sufficiently large N. Indeed, 1/w+4πs/τ→0
uniformly for primes p∈[X1/2,X1].
Using the trivial bound ∣R∣≤A and (L8), the major-arc contribution
to J−I is at most
KDβNAZ1Z2w.
Together with (L9), this gives
∣J−I∣≤K4DβNAZ1Z2w.(L12)
But 1/p≥w/N, so (L5) and (L12) imply
I≥(crep−K4Dβ)NAZ1Z2w>0.
Here crep=0.996/16 and 4Dβ/K=4⋅10−6.
This contradicts I=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) with j≥2, put
bz=⌊z1/dj⌋dj.
For all sufficiently large j, uniformly in this range of z,
bz≥z/2≥Nj−2. To see the first inequality, write
x=z1/dj and use
zbz≥(1−1/x)dj≥1−xdj≥21.
The last inequality holds uniformly since
x≥Nj−11/dj grows faster than dj. The second follows
from Nj−1=Nj−22 and Nj−2≥2. Thus
bz∈Bj⊆Φ2. The mean value theorem also gives
0≤z−bz≤djz1−1/dj.(H1)
When 1≤z≤N and Nk−1≤N<Nk, the relevant index
j is at most k. The degrees dj are nondecreasing. Hence the
right side of (H1) is at most
ΔN=dkN1−1/dk.
The finitely many initial ranges not covered by the uniform argument
are contained in some fixed [1,N∗]. They can use 1∈B0 as
the preceding element; for large N, ΔN≥N∗. We have
therefore proved that, for every z∈[1,N], some
bz∈Φ2 satisfies z−ΔN≤bz≤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/2, (G4) yields
X1ΔN≤(1+o(1))dkexp(−nk0.9logN)⟶0.(H2)
For large N, apply this preceding-power assertion to the upper
endpoint Y2 in (L). As ΔN<X1/4≤Y2−Y1, it supplies
ϕ2∈Φ2∩[Y1,Y2]. By the definition of DN,
ϕ2=m−f−ϕ1−ϕ1′
for some m∈MN, f∈F, and
ϕ1,ϕ1′∈Φ1. Consequently
m=f+ϕ1+ϕ1′+ϕ2∈F+Φ⊆F1,
contrary to m∈MN. This proves (G).
Every cutoff and the density increment
All thresholds above depend only on β: the fourth lemma uses
b,β, the prime-selection lemma uses
γ0=ββ1/800, and the remaining conditions follow from
the displayed uniform limits and the fixed power construction. Choose
an integer Nβ≥1 beyond all of them. Then (G) holds for every
N>Nβ and every F with σ(F)≥β.
For 1≤N≤Nβ, positive Schnirelmann density implies
1∈F. If F omits a point of [1,N], its first omitted point
has a predecessor in F, so it belongs to F+1. Since
{0,1}⊆Φ,
∣F1∩[1,N]∣≥∣F∩[1,N]∣+1≥βN+1.
If no point is omitted, the count is N. Set
φ(β)=min{δ,Nβ1,1−β}>0.
The two small-cutoff cases and (G) prove (E) for every positive integer
N. Together with (C4), this proves the asserted non-basic
essential-component construction. □
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∈Φ and F⊆F+Φ (p. 77). Minkowski sums
of the positive sets give minΦ=3, so the stated theorem adjoins
{0,1} explicitly as Φ.
P. 70: construction. The cutoffs bound the powers, and all the
half-degree blocks start at B0. The English prefix union is retained
exactly. Bounds on the bases and omission of B0,B1 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, as proved on the preliminary-lemmas page.
P. 71: counts and initial index. Odd degrees require a count such
as Pi3, and the geometric series cannot be bounded by two.
The second printed crossing inequality uses Pk0−1, not
logPk0−1. Choosing a sufficiently large j0≥2
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 Z2 bound. Here the corrected fourth
lemma is applied directly at H and yields (G3). Also Z1 counts
the restricted set MN, not the whole complement.
Pp. 72–76: the two scales. The source uses
X1=N1−1.1/nk and later
τ=(β1N/10)1−1/nk. Its fifth-lemma display on p. 72
has an inconsistent factor 1/2 versus 1/4; Section 5 uses the
latter. Here integer X1 retains the source's N scale, while
τ belongs to the explicitly truncated H scale. Equation
(L10) proves the comparison actually needed.
Pp. 73–74: signs, membership and positivity. The printed S2
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 ∈ on p. 73 denotes
non-membership. The product includes T0, so its sums lie
in the stated prefix union. The fixed value M=1∈Φ1 replaces
the printed power at the βN/40 scale. Full lower blocks and
a final block truncated at H satisfy (L2), which proves (L4).
The source's displayed supports up to N 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′, with nk′=⌊nk/2⌋. 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)⌋ and a compressed description of
Φ1 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) gains a fixed
φ(β)>0 in density at every cutoff. The sum uses all elements
of the set at once, whereas Problem 38 asks that for every A and every
cutoff N a single element b give A∪(A+b) the gain up to N, so
the result does not by itself answer the problem.