Let N denote a sufficiently large real number. In this paper, we prove that for 1<c<10434977419, c≠43, for almost all real numbers T∈(N,2N] (in the sense of Lebesgue measure), the Diophantine inequality |pc1+pc2−T|<T−910c(10434977419−c) is solvable in primes p1,p2. In addition, it is proved that the Diophantine inequality |pc1+pc2+pc3+pc4−N|<N−910c(10434977419−c) is solvable in primes p1,p2,p3,p4. This result constitutes a refinement upon that of Li and Cai.
Citation: Jing Huang, Qian Wang, Rui Zhang. On a binary Diophantine inequality involving prime numbers[J]. AIMS Mathematics, 2024, 9(4): 8371-8385. doi: 10.3934/math.2024407
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Let N denote a sufficiently large real number. In this paper, we prove that for 1<c<10434977419, c≠43, for almost all real numbers T∈(N,2N] (in the sense of Lebesgue measure), the Diophantine inequality |pc1+pc2−T|<T−910c(10434977419−c) is solvable in primes p1,p2. In addition, it is proved that the Diophantine inequality |pc1+pc2+pc3+pc4−N|<N−910c(10434977419−c) is solvable in primes p1,p2,p3,p4. This result constitutes a refinement upon that of Li and Cai.
The Waring-Goldbach problem is that every natural number n can be represented as the type
n=pk1+⋯+pks, |
where s and k are given positive integers and p1,⋯,ps are prime variables. This well-known problem has spawned many analogues, which has attracted a large number of scholars to investigate and obtain many celebrated results. For instance, given c>1 is not an integer and ε>0. For every sufficiently large real N, suppose that h(c) is the smallest natural number s satisfying the inequality
|pc1+pc2+⋯+pcs−N|<ε | (1.1) |
with solutions in primes p1,⋯,ps. Piatetski-Shapiro showed in [13] that
lim supc→∞h(c)clogc≤4, |
and h(c)≤5 holds for 1<c<32. Based on this result and Vinogradov's three prime theorem, we can conjecture that h(c)≤3 for c near one. Tolev [14] first proved this conjecture. More precisely, Tolev [15] showed that, if 1<c<1514, the inequality has solutions in primes p1,p2,p3:
|pc1+pc2+pc3−N|<ε, |
where ε=N−1c(1514−c)log9N. Subsequently, this result was constantly improved by several authors (see [1,2,3,4,7,8]).
In 1999, Laporta [10] considered the corresponding binary problem. If 1<c<1514 fixed and ε=T1−1514clog8T, the following inequality
|pc1+pc2−T|<ε | (1.2) |
has a solution for all real numbers T∈(N,2N]∖T with |T|=O(Nexp(−13(logNc)15)). Later, the exponent of c was improved to
4336=1.944444⋯, 65=1.2, 5944=1.340909⋯ |
by Zhai and Cao [16], Kumchev and Laporta [9], and Li and Cai [11] successively.
In 2003, Zhai and Cao [17] first proved that the inequality
|pc1+pc2+⋯+pc4−N|<ε | (1.3) |
is solvable, where 1<c<8168. Afterwards, the exponent of c was improved to
9781=1.197530⋯, 65=1.2, 1193889=1.341957⋯ |
by Mu [12], Zhang and Li [18], and Li and Zhang [19] successively.
Here, we consider the cases s=2 and s=4 in inequality (1.1), and enlarge the exponent of c. Our results are as follows:
Theorem 1. Assume 1<c<10434977419, c≠43, and N is a sufficiently large real number. Suppose ε=T−910c(10434977419−c), and B0(T) is the number of solutions of inequality (1.2). Then, for all real numbers T∈(N,2N]∖T with |T|=O(Nexp(−13(logNc)15)), we obtain
B0(T)≫εT2c−1log2T. |
Theorem 2. Assume 1<c<10434977419, c≠43, and N is a sufficiently large real number. Suppose ε=T−910c(10434977419−c), and B0(N) is the number of solutions of inequality (1.3). Then, we obtain
B0(N)≫εN4c−1log4N. |
In this paper, our improvement mainly comes from the estimates of exponential sums. We transform the exponential sum into Type Ⅰ and Type Ⅱ sums by using Heath-Brown's identity. As a result, we improve the previous results by enlarging the upper bound of c. In addition, by using Lemma 2.8, the value of c=43 can be excluded.
Now, we will give some notations which are required throughout the paper.
Throughout this paper, suppose that N is a sufficiently large integer, Λ(n) stands for the von Mangoldt function, and |T| is the cardinality of the set T. a∼A means A<a≤2A. As usual, the constants in the ≪-symbols and O-terms are absolute or depend only on c.
In addition, we write
1<c<10434977419, c≠43; X=N1c4, ι=X50489154838−c2,K=X10434977419−c, e(t)=e2πit, ε=N−910c(10434977419−c),δ=11000(10434977419−c), E=exp(−(logNc)15),P=(2E2)13logN, S(t)=∑p∼Xe(pct)logp,I(t)=∫2XXe(uct)du. |
Next, we shall recall some preliminary lemmas that are necessary in this paper.
Lemma 2.1 ([15, Lemma 1]). Assume that ξ(y) is a function which is ω=[logX] times continuously differentiable and satisfies
{ξ(y)=1, |y|≤45ε,0<ξ(y)<1, 45ε<|y|≤ε,ξ(y)=0, |y|≥ε. |
For its Fourier transformation
Ξ(t)=∫∞−∞e(−ty)ξ(y)dy, |
then
|Ξ(t)|≤min(95ε,1π|t|,1π|t|(5ωπ|t|ε)ω). |
Lemma 2.2. ([15, Lemma 14]). If |t|≤ι, then
S(t)=I(t)+O(Xexp(−log15X)). |
Lemma 2.3 ([5, Lemma 3.1]). There is a trivial bound that
I(t)≪X1−c|t|−1. | (2.1) |
Lemma 2.4 ([15, Lemma 7]). There exist the following inequalities
(i)∫|t|<ι|S(t)|2dt≪X2−clog3X; | (2.2) |
(ii)∫|t|<ι|I(t)|2dt≪X2−clog3X; | (2.3) |
(iii)∫n+1n|S(t)|2dt≪Xlog3X uniformly in n. | (2.4) |
Lemma 2.5. We have
(i)∫∞−∞I2(t)Ξ(t)e(−Tt)dt≫εT2c−1, | (2.5) |
(ii)∫∞−∞I4(t)Ξ(t)e(−Nt)dt≫εX4−c. | (2.6) |
Proof. The above two inequalities (2.5) and (2.6) can be found in [9] and [17] independently.
Lemma 2.6 ([6, Lemma 5]). For any complex number αn, we have the inequality
|∑H≤n≤2Hαn|2≤(1+HU)∑0≤|u|≤U(1−|u|U)(∑H≤n≤2H−uαn+u¯αn), |
where H⩾1, U≤H, and ¯αn stands for the conjugate of αn.
Lemma 2.7 ([11, Lemma 2.3]). Suppose |D|>0 and A≤A′≤10A, then the inequality
∑A≤a≤A′e(Dac)≪(|D|Ac)κAλ−κ+A|D|Ac |
holds for any exponent pair (κ,λ) with 0≤κ≤12≤λ≤1.
Lemma 2.8 ([1, Therorem 2]). Suppose τ, υ are real numbers such that
τυ(τ−1)(υ−1)(τ−2)(τ+υ−2)(τ+υ−3)(τ+2υ−3)(2τ+υ−4)≠0. |
Let
∑I=∑a≤Aα(a)∑b∈Iae(Daτbυ), |
where D>0, A≥1, B≥1, |α(a)|≤1, and Ia is a subinterval of [B,2B]. Assume G=DAτBυ. For any η>0, then
∑I≪(G314A4156B2956+G15A34B1120+G18A1316B1116+A34B+AB34+G−1AB)(AB)η. |
Lemma 2.9 ([10, Lemma 1]).
V=maxN<v2≤2N∫2NN|∫ι<|t|≤Ke((v1−v2)t)dt|dv1≪logN. |
Lemma 2.10 ([10, Lemma 2]). Let the letters C and R be the sets of complex and real numbers, respectively. Suppose that ϝ1 and ϝ2 are measurable subsets of Rn, and
‖g‖i=(∫ϝi|g(t)|2dt)12, ⟨g,f⟩i=∫ϝig(t)¯f(t)dt |
stand for the usual norm and inner product in L2(ϝi,C) (i=1,2), respectively.
Assume ϖ is a measurable complex-valued function defined on ϝ1×ϝ2, then
supy∈ϝ1∫ϝ2|ϖ(y,t)|dt<+∞, supt∈ϝ2∫ϝ1|ϖ(y,t)|dt<+∞. |
Hence,
|∫ϝ1ϕ(y)⟨ψ,ϖ(y,⋅)⟩2dy|≪‖ψ‖2‖ϕ‖1(supy′∈ϝ1∫ϝ1|⟨ϖ(y,⋅),ϖ(y′,⋅)⟩2|dy)12, |
where ϕ∈L2(ϝ1,C), ψ∈L2(ϝ2,C).
In this section, we transform the exponential sum into Type Ⅰ and Type Ⅱ sums by taking advantage of Lemma 3.1.
Lemma 3.1 ([6, Lemma 3]). For 3<L<M<Q<X, {Q}=12, X≥64Q2L, Q≥4L2,and M3≥32X, if G(n) is a complex valued function satisfying |G(n)|≤1, then the sum
∑X≤n≤2XΛ(n)G(n) |
may be decomposed into O(log10X) sums, each either of type I:
∑A≤a≤2Aα(a)∑B≤b≤2BG(ab) |
with B>Q, AB≍X, |α(a)|≪aη, or of type II:
∑A≤a≤2Aα(a)∑B≤b≤2Bβ(b)G(ab) |
with L≪B≪M, AB≍X, |α(a)|≪aη,|β(b)|≪bη.
Lemma 3.2. For any η>0, α(a) is a sequence of complex numbers satisfying |α(a)|≪aη. If ι≤|t|≤K and A≪X36858279056017314356, then
SI=∑a≤Aα(a)∑X≤ab≤2Xe(t(ab)c)≪X14171932031504328589+2η, |
where c∈(1,10434977419] and c≠43.
Proof. Suppose A≪X368582790510530300123, and we use Lemma 2.7 by choosing the exponent pair (27,47), then
SI≪Aη∑a≤A|∑X≤ab≤2Xe(t(ab)c)|≪Aη∑a≤A((|t|Xc)27X27+1|t|Xc−1a)≪X14171932031504328589+2η. |
In addition, suppose X368582790510530300123≪A≪X36858279056017314356, then from Lemma 2.8 we derive that
SI=Aη∑a≤Aa(m)Aη∑X≤ab≤2Xe(t(ab)c)≪((KXc)314A314X2956+(KXc)15A15X1120+(KXc)18A18X1116+A−14X+A14X34+(ιXc)−1X)X2η≪X14171932031504328589+2η. |
Combining the above two cases, we complete the proof of this lemma.
Lemma 3.3. For any η>0, α(a) and β(b) are sequences of complex numbers satisfying |α(a)|≪aη, |β(b)|≪bη. If ι≤|t|≤K and X1742707721504328589≪A≪X4271647518750251190813782635796, then
SII=∑A<a≤2Aα(a)∑X<ab≤2Xβ(b)e(t(ab)c)≪X14171932031504328589+3η. |
Proof. Let U=X1742707721504328589−η. Cauchy's inequality and Lemma 2.6 gives us
|SII|≪(∑b∈Ia|β(b)|2)1/2(∑b∈Ia|∑A<a≤2Aα(a)e(t(ab)c)|2)1/2≪X2η(X2U+XU∑1≤u≤U∑A≤a≤2A−u|Eu|)1/2, | (3.1) |
where Ia stands for a subinterval of [X2A,2XA], and Eu=∑b∈Iae(tbc((a+u)c−ac)).
Following from Lemma 2.7 and choosing the exponent pair (1331,1631), we obtain the estimate of Eu:
Eu≪(|t|Xc−1u)1331X1631A−1631+1|t|Xc−1u. |
Then, taking the estimate of Eu into (3.1), we get
|SII|≪X2η(X2U+XU(U4431|K|1331X1331c+331A1531+X1−c|ι|−1AlogU))1/2≪X14171932031504328589+3η. |
Lemma 3.4. Assume that η is any arbitrarily small positive number and ι≤|t|≤K, then
S(t)≪X14171932031504328589+5η, |
where c∈(1,10434977419] and c≠43.
Proof. First of all, we define
M(t)=∑n∼XΛ(n)e(nct). |
Obviously, we can deduce that
S(t)=M(t)+O(X12). | (3.2) |
Suppose
L=X1742707721504328589, M=X4271647518750251190813782635796, Q=[X23314864516017314356]+12. |
Following from Lemma 3.1 with G(n)=e(tnc), we reduce the sum M(t) of type Ⅰ:
∑A≤a≤2Aα(a)∑B≤b≤2BG(ab), B>Q |
or of type Ⅱ:
∑A≤a≤2Aα(a)∑B≤b≤2Bβ(b)G(ab),L≪B≪M. |
From this combined with Lemmas 3.2 and 3.3, we deduce
M(t)≪X14171932031504328589+5η. |
Inserting the bound of M(t) into (3.2), we finish the proof of Lemma 3.4.
In this section, we shall give the details of the proof of Theorem 1.
Let ξ(y) and Ξ(t) stand for the functions that appear in Lemma 2.1. For T∈[N,2N], we write
B(T)=∑p1,p2∼X|pc1+pc2−T|<ε(logp1)(logp2). |
It suffices to show that B(T)≥B1(T), where
B1(T)=∑X<p1,p2≤2X(logp1)(logp2)∫∞−∞e((pc1+pc2−T)t)Ξ(t)dt=∫∞−∞S2(t)Ξ(t)e(−Tt)dt=(∫|t|≤ι+∫ι<|t|≤K+∫|t|>K)S2(t)Ξ(t)e(−Tt)dt=Q1(T)+Q2(T)+Q3(T). |
In addition, we write
P(T)=∫∞−∞I2(t)e(−Tt)Ξ(t)dt, P1(T)=∫ι−ιI2(t)Ξ(t)e(−Tt)dt. |
Lemma 4.1. We have
∫ι<|t|≤K|S(t)|2|Ξ(t)|dt≪Xlog4X. |
Proof. It follows from Lemma 2.1 and (2.4) that
∫ι<|t|≤K|S(t)|2|Ξ(t)|dt≪ε∑0≤n≤1ε∫n+1n|S(t)|2dt+∑1ε−1≤n≤K1n∫n+1n|S(t)|2dt≪Xlog4X. |
Lemma 4.2. We have
∫ι<|t|≤K|S(t)|4|Ξ(t)|dt≪ε12X100073329693008657178−c2+12δ. |
Proof. If V(t) is a continuous function defined for −K≤t≤K, then we find that
|∫ι<|t|≤KS(t)V(t)dt|=|∑X<p≤2X(logp)∫ι<|t|≤KV(t)e(pct)dt|≤∑X<p≤2X(logp)|∫ι<|t|≤KV(t)e(pct)dt|≤(logX)∑X<m≤2X|∫ι<|t|≤KV(t)e(mct)dt|. | (4.1) |
Suppose H(t)=∑m∼Xe(mct). Using Cauchy's inequality, we deduce that
|∫ι<|t|≤KS(t)V(t)dt|≤X12(logX)|∑X<m≤2X|∫ι<|t|≤KV(t)e(mct)dt|2|12=X12(logX)|∑X<m≤2X∫ι<|t|≤KV(t)e(mct)dt∫ι<|y|≤K¯V(y)e(mcy)dy|12=X12(logX)|∫ι<|y|≤K¯V(y)dy∫ι<|t|≤KV(t)H(t−y)dt|12≤X12(logX)|∫ι<|y|≤K|V(y)|dy∫ι<|t|≤K|V(t)||H(t−y)|dt|12. | (4.2) |
Then, we estimate the inner integral in (4.2).
First, we need to consider H(t−y). Following from Lemma 2.7 and choosing the exponent pair (1912658293,3136958293), we obtain that the inequality
H(t)≪(|t|Xc)1912658293X1224358293+X|t|Xc |
holds for X−c<|t|≤2K.
Combining with the trivial upper bound H(t−y)≪X, we get
H(t−y)≪min((|t−y|Xc)1912658293X1224358293+X|t−y|Xc,X). | (4.3) |
Next, inserting the estimate of H(t−y) into the inner integral in (4.2), we find that
∫ι<|t|≤K|V(t)||H(t−y)|dt≪∫ι<|t|≤K|t−y|≤X−c|V(t)||H(t−y)|dt+∫ι<|t|≤KX−c<|t−y|≤2K|V(t)||H(t−y)|dt≪X∫ι<|t|≤K|t−y|≤X−c|V(X)|dt+∫ι<|t|≤KX−c<|t−y|≤2K|V(t)|((|t−y|Xc)1912658293X1224358293+1|t−y|Xc−1)dt≪Xmaxι<|t|≤K|V(t)|∫|t−y|≤X−cdt+X9812065971504328589∫ι<|t|≤K|V(t)|dt | (4.4) |
+X1−cmaxι<|t|≤K|V(t)|∫X−c<|t−y|≤2K1|t−y|dt≪X9812065971504328589∫ι<|t|≤K|V(t)|dt+X1−c(logX)maxι<|t|≤K|V(t)|. | (4.5) |
From (4.2) and (4.4), we have
|∫ι<|t|≤KS(t)V(t)dt|≪X24855351863008657178(logX)∫ι<|t|≤K|V(t)|dt+X1−c2(log32X)|maxι<|t|≤K|V(t)|∫ι<|t|≤K|V(t)|dt|12. | (4.6) |
Taking V(t)=|Ξ(t)|¯S(t)|S(t)|, from Lemmas 3.4 and 4.1 and (4.6), we get
∫ι<|t|≤K|Ξ(t)||S(t)|3dt=∫ι<|t|≤KV(t)S(t)dt≪X12427675981504328589(logX)∫ι<|t|≤K|Ξ(t)||S(t)|2dt+ε12X29215217921504328589−c2+6δ|∫ι<|t|≤K|Ξ(t)||S(t)|2dt|12≪X27470961821504328589log5X+ε12X73473721733008657178−c2+7δ≪X27470961821504328589+7δ. | (4.7) |
Next, taking V(t)=|Ξ(t)|¯S(t)|S(t)|2, by Lemma 3.4, (4.6), and (4.7), we obtain
∫ι<|t|≤K|S(t)|4|Ξ(t)|dt=∫ι<|t|≤KV(t)S(t)dt≪X12427675981504328589(logX)∫ι<|t|≤K|S(t)|3|Ξ(t)|dt+ε12X24200789291002885726−c2+8δ|∫ι<|t|≤K|S(t)|3|Ξ(t)|dt|12≪X39898637801504328589+8δ+ε12X100073329693008657178−c2+12δ≪ε12X100073329693008657178−c2+12δ. |
Lemma 4.3 ([11, Lemma 3.3]). We have
∫2NN|Q1(T)−P1(T)|2dT≪ε2N4c−1E13. |
Lemma 4.4. We have
∫2NN|Q2(T)|2dT≪ε2N4c−1E13. |
Proof. Suppose
ϝ1={T:T∼N}, ϝ2={t:ι<|t|≤K}. |
Taking advantage of Lemma 2.10 with ψ(t)=Ξ(t)S2(t),ϖ(t,T)=e(Tt),ϕ(T)=¯Q2(T), we obtain
∫2NN|Q2(T)|2dT=∫ϝ1¯Q2(T)⟨Ξ(t)S2(t),e(tT)⟩2dT≪(∫ϝ2|Ξ(t)S2(t)|2dt)12(∫ϝ1|¯Q2(T)|2dT)12(supt′∈ϝ1∫ϝ1|⟨e(tT),e(t′T)⟩2|dt)12. | (4.8) |
According to Lemmas 2.1, 2.9, and 4.2, we get
∫2NN|Q2(T)|2dT≪V∫ι<|t|≤K|S(t)|4|Ξ(t)|2dt≪ε(logN)∫ι<|t|≤K|S(t)|4|Ξ(t)|dt≪ε32X100073329693008657178−c2+12δlogN≪ε2N4c−1E13. |
Hence, we finish the proof of this lemma.
Lemma 4.5. We have
∫2NN|Q3(T)|2dT≪N. |
Proof. It follows from the estimate of Ξ(t) in Lemma 2.1 that
∫2NN|Q3(T)|2dT≪N|∫t≥K|S2(t)||Ξ(t)|dt|2≪NX4|∫t≥K(5ωπtε)ωdtt|2≪NX4(5ωπKε)2ω≪N. |
Lemma 4.6. We have
∫2NN|B1(T)−P(T)|2dT≪ε2N4c−1E13. |
Proof. We obtain
∫2NN|B1(T)−P(T)|2=∫2NN|Q1(t)−P1(T)+Q2(t)+Q3(t)+P1(T)−P(T)|2 | (4.9) |
≤∫2NN|Q1(T)−P1(T)|2dT+∫2NN|Q2(T)|2dT+∫2NN|Q3(T)|2dT+∫2NN|P(T)−P1(T)|2dT. | (4.10) |
For the last integral, we will use Lemmas 2.1 and 2.3 to estimate and obtain
∫2NN|P(T)−P1(T)|2dT≪∫2NN∫|t|>ι|I(t)|4|Ξ(t)|2dtdT≪NX4−4c∫|t|>ι|Ξ(t)|2|t|−4dt≪ε2NX4−4cι−3. | (4.11) |
From (4.9) and (4.11), we have
∫2NN|B1(T)−P(T)|2dT≪∫2NN|Q1(T)−P1(T)|2dT+∫2NN|Q2(T)|2dT+∫2NN|Q3(T)|2dT+ε2NX4−4cι−3≪ε2N4c−1E13, | (4.12) |
where Lemmas 4.3, 4.4, and 4.5 are employed.
Lemma 4.6 implies
B1(T)=P(T)+O(εN2c−1E19), | (4.13) |
where T∈(N,2N]∖T with |T|=O(NE1/3).
Then, it follows from (4.13) and (2.5) that
B0(T)≥B(T)log22X≥B1(T)log22X≥P(T)log22X≫εT2c−1log2T. | (4.14) |
Thus, we finish the proof of Theorem 1.
Suppose
B(N)=∑X<p1,⋯,p4≤2X|pc1+⋯+pc4−N|<ε(logp1)⋯(logp4). |
It follows from the definition of ξ(y) and Ξ(t) in Lemma 2.1 that
B(N)≥B1(N), | (5.1) |
where
B1(N)=∫∞−∞S4(t)Ξ(t)e(−Nt)dt=(∫ι−ι+∫ι<|t|≤K+∫|t|>K)S4(t)Ξ(t)e(−Nt)dt=Q1(N)+Q2(N)+Q3(N). | (5.2) |
First of all, we need to estimate Q1(N). Let
P1(N)=∫ι−ιI4(t)Ξ(t)e(−tN)dt,P(N)=∫∞−∞I4(t)Ξ(t)e(−tN)dt, |
then we find that
Q1(N)=∫ι−ιS4(t)Ξ(t)e(−Nt)dt=P(N)+(P1(N)−P(N))+(Q1(N)−P1(N)). | (5.3) |
For the second integral in (5.3), we use Lemmas 2.1 and 2.3 to estimate and obtain
|P1(N)−P(N)|≪∫ι−ι|I(t)|4|Ξ(t)|dt≪X4−4c∫|t|>ι|Ξ(t)||t|−4dt≪εX4−4cι−3≪εX4−clogX. | (5.4) |
For the third integral in (5.3), we use Lemmas 2.1 and 2.2 to estimate and get
|Q1(N)−P1(N)|≪∫|t|≤ι|S4(t)−I4(t)||Ξ(t)|dt≪εmax−ι≤t≤ι|S(t)−I(t)|∫|t|≤ι(|S(t)|+|I(t)|)(|S(t)|2+|I(t)|2)dt≪εXexp(−log15X)X∫|t|≤ι(|S(t)|2+|I(t)|2)dt≪εX2exp(−log15X)X2−c(log3X)≪εX4−cexp(−log15X), | (5.5) |
where (2.2) and (2.3) in Lemma 2.4 are utilized. Combining (2.6) and (5.3)–(5.5), we derive that
Q1(N)≫εX4−c. | (5.6) |
From Lemma 4.2, we have
Q2(N)≪∫ι<|t|≤K|S(t)|4|Ξ(t)|dt≪ε12X100073329693008657178−c2+12δ≪εX4−clogX. | (5.7) |
From Lemma 2.1, we obtain
Q3(N)≪∫K−K|S4(t)||Ξ(t)|dt≪X4∫K−K(5ωπ|t|ε)ωdt|t|≪X4(5ωπKε)ω≪1. | (5.8) |
It follows from (5.2), (5.6)–(5.8) that
B1(N)≫εX4−c. | (5.9) |
From (5.1) and (5.9), we have
B0(N)≥B(N)log42X≥B1(N)log42X≫εN4c−1log4N. | (5.10) |
Hence, we finish the proof of Theorem 2.
The authors declare they have not used Artificial Intelligence (AI) tools in the creation of this article.
The paper is supported by National Natural Science Foundation of China (Grant No. 12171286).
The authors declare that they have no conflict of interest.
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