which contradicts to the growth above. So can not have the complex roots and does not have the factor . Therefore both RC2 and RC are proved. We have seen that the two-dimensional problem is reduced to one-dimension and the one-dimensional is reduced to its product expression. Perhaps this is close to the original idea of Riemann. Other results are also discussed by geometric analysis in the last section.
Riemann hypothesis (RH) is one of the most difficult problems in mathematics, which is reviewed in     . We shall consider . Although and have the same zeros, but their properties are quite different. has the symmetry, i.e. on the critical line, and are alternative oscillation with single peak outside critical line, which geometrically implies RC true. Whereas the property of is bad, even if on critical line are not alternative oscillation, sometimes almost tangent and multiple peak. Studying is very hard.
To study Riemann conjecture (RC), we have proposed a framework of geometric analysis for in previous papers. If three theorems are proved, then RC holds, also see section 3. Firstly we have proved theorems 1 and 2 by the symmetry of . But to prove theorem 3: “on critical line is single peak”, we have met essential difficulty. The symmetry is not enough and the stronger tool is needed. Thus we have to focus our attention on and re-investigate Riemann’s thought. We have found two mysteries in it finally proved RC by method of analysis.
Denote . Riemann -function has an integral expression , p.17,
But Riemann did not use (1.1), he had directly taken to get the real function , p. 301,
Why Riemann preferred (1.2) rather than (1.1)? This is the first mystery.
Riemann also regarded t as a complex variable (very important!). Taking and using the uniqueness of analytic function, we get
Thus the first mystery is formulated as:
Equivalence. is uniquely determined by its initial value , i.e., two dimensional problem is reduced to one dimension.
We also consider the initial value problem of Cauchy-Riemann system
As is analytic, Cauchy-Kovalevshkaya theorem confirms that it has a unique analytic solution. This solution just is . Actually, by direct verification,
then (1.3) and the equivalence hold yet. Here resembles a traveling-wave solution of the wave equation, where as an initial value. We had used it in previous papers.
We see that Riemann had studied rather than , his thought can be formulated as:
Riemann conjecture(RC). All zeros of lie on critical line .
To study , we find the second mystery in Riemann’s paper  (pp. 301-302).
Riemann conjecture 2 (RC2). Using all zeros of can uniquely determine
For k-ple zeros, should take k-ple products.
The greatest mystery is that RC2 implies RC. Actually, if , replacing t by in (1.5), each factor , then and RC holds.
We rigorously have proved RC2 by the method of analysis in section 2. Here we briefly formulate our basic idea as follows. Consider functional equation
It is known that on critical line
we get the upper bound of growth
To prove RC2, by contradiction. If has conjugate complex roots , , by symmetry , then do yet. Thus by equivalence must contain four factors
Letting , contains a real factor
and then contains a term (the lower bound)
which contradicts (1.7). So can not have complex roots and does not have the factor . Therefore both RC2 and RC are proved.
Our main contribution is that we for the first time have regarded RC as an initial value problem, found these mysteries and proposed the newest method to prove Riemann conjecture.
Similar work has not been found in other papers and books.
We shall continue to complete the geometric analysis of in section 3.
2. Analytical Proof of RC and RC2
2.1. Two Holes in Riemann’s Analysis
Riemann denoted by in his paper. He pointed out, see  (pp. 301-302).
“If one denotes by the roots of the equation , then one can express as
because, since the density of roots of size t grows only like as t grows, this expression converges and for infinite t is only infinite like ; Thus it differs from by a function of t2 which is continuous and finite for finite t and which, when divided by t2, is infinitely small for infinite t. This difference is therefore a constant, the value of which can be determined by setting .”
Because Riemann did not use , we must regard α to be real roots, this is extremely important! But then it is misunderstood.
We now explain his analysis. On critical line is an even entire function and has infinite number of zeros . We consider formally the remainder of ,
One knows (We have better , , ). Thus
This series (R) converges for finite t. (Riemann said) has the growth (This expression is not suitable. We shall use , which admits = 0, see (2.6)). The series (R) differs from by a function of t2, which, when divided by t2, is infinitely small for infinite t. (Riemann said) “This difference is therefore a constant.” This is not rigorous, in general, it should be rather than a constant. There is a hole of the uniqueness.
Hadamard in 1893 proved product formula for general entire function, see  (p. 20),  (p. 16). Denoting , , the zeros of are conjugate, one gets
which is even if , then . Taking , then .
But this Hadamard’s way from to implies a serious contradiction. If all zeros are real, then which itself assumes RC. If conjugate complex zeros are admitted, which just denies RC. Hadamard’s theorem was referred by Von Mangoldt “The first real progression in the field in 34 years”, see , p. 39. We think this is a misunderstanding. Actually, Hadamard’s way is independent of proving RC and far from Riemann’s thought. Our idea is to consider at as an initial value. We shall directly prove RC2 by method of analysis, so this contradiction is cast off.
2.2. Analytical Proof of RC and RC2
We consider the functional equation
Firstly, has asymptotic expansion
Take logarithm and decompose the real part, ,
Besides, and , we get
Secondly, there are growths of for large t, , p. 185, p. 200,
We only need the estimate of , also see Remark 1.
Thus, we get an upper bound of growth (note: not )
So is admitted.
Finally, to prove RC2 (or RC), by contradiction. If has conjugate complex roots , , , by symmetry , then do yet. Denoting and using the equivalence, must contain four factors
Letting , then must contain a real polynomial of fourth degree
and contains a term (as a lower bound)
Its growth contradicts (2.6). Thus can not have complex roots and does not have the factor . Therefore both RC and RC2 are rigorously proved.
Originally we want to prove only RC2, fortunately, both RC and RC2 are proved.
Remark 1. In period of Riemann, no estimates (2.5), but it is possible to prove RC. As
is already continued analytically to (actually this is Euler’s method). Thus
and gets an coarse estimate (e.g. in , p. 27)
By (2.8) one can still prove that does not have complex roots. But nobody noted it. Therefore I feel, Riemann had already approached to prove RC. Our proof is completed to follow Riemann’s thought.
Numerical experiments 1. Using the data of the first 105 zeros in Odlyzko , we have computed and in (1.2) for . We draw these curves by variable scale , here , . We see in Figure 1 that approximates very well, of course, larger is t, then larger is its deviation.
We have for the first time computed and Figure 1, which make us believe the correctness of RC2, and then consider its analytic proof as before.
3. Continuation of Geometric Analysis
In previous papers   , we have proposed geometric analysis and proved three results:
Theorem 1. If is single peak and single zero, then the peak-valley structure for and RC hold.
Theorem 2 (old). If two roots of are very close to each other (including double zeros), then the peak-valley structure for and RC still hold.
Theorem 3. is single peak.
RC can be derived by these three theorems. We at present re-examine these theorems. Theorem 1 is correct, see section 3.1. Theorem 2 is also correct but uncomplete, which is generalized in section 3.4. The original proof of theorem 3  has defect (see section 3.2), which is derived by RC2 in section 3.3.
3.1. A Concise Proof of Theorem 1
Consider a root-interval of , obviously and depend on . Assume inside for . At the left end , and , then the slop , (which was proved in  ) we have
At the right end , and , similarly,
Figure 1. approximates by zeros .
Because has opposite signs at two ends of , there surely exists some inner point such that . Then is valley and form a peak-valley structure. There is a positive lower bound independent of .
So RC holds in . Because the zeros of analytical function do not have finite condensation point, then any finite t surely falls in some . RC holds for any t.
3.2. Defect in Original Proof of Theorem 3
To prove to be single peak, we discussed monotone growth of the argument of in  and used Riemann’s estimate . As is of super-linear growth, when t increases to , the increment slowly increases,
whereas , then claimed that monotone increases. But here is not correct, which may be . We consider Riemann’s symmetrization
(here the decay factor is reduced) and have
Thus the local argument in root-interval .
We see in Figure 2 (also see   ) that jumps by 1 at zero of , then linearly decreases in with the slope . Whereas has slope . It seems , and difficult to prove . Besides, as , this research is not suitable.
This defect makes us turn to on critical line and re-investigate RC2.
3.3. Revision Proof of Theorem 3
By RC2, take logarithm and derivation to get
Consider root-interval and decompose the summation into three parts.
Figure 2. Curves . S jumps by 1 twice in .
Note that inside has same sign. We investigate each sum
For , are finite. If t is close to , then tends to . If t is close to , then tends to . There surely exists some inner point such that . We show this point is unique. For this we consider their derivatives
Thus all are monotone decreasing for , their sum does yet. Therefore this zero of is unique and then is single peak. This proves theorem 3.
Using Lagarias’s positivity  (RC is assumed), we get monotone growth , p. 344,
This is a clear description for RC. Therefore Riemann -function has mathematical beauty: The symmetry, single peak and monotone growth (i.e. the ordering).
3.4. Theorem 2 Holds for m-ple Zeros
In large scale computations     all zeros of are single, no multiple zeros are found. People believe there are only single zeros, but so far do not prove. We have to skirt round the difficulty to prove theorem 2. We shall extend theorem 2 (old) as:
Theorem 2. If has m-ple zeros on critical line, then for small will bifurcate into m alternative oscillations with single peak, and RC still holds.
Proof. Assume that there are three consecutive zeros of on critical line , which form two root-intervals, and is a m-ple zero, . Denote and . Denoting and the origin , and fixing a small , we discuss a circle with ( to be defined). Assume that the real function has m-ple zero at O
These coefficients and are of same order. Thus
Below we discuss , and temporarily omit high-order remainder.
Using and De Moivre formula we have
and discuss and respectively.
1) The zeros of satisfy , i.e.
which are symmetric with respect to . If even, then all . If odd, the middle argument satisfies , i.e. original point .
Taking the roots , i.e. , we have and re-arrange the ordering of these m zeros as
2) The zeros of satisfy , i.e.,
here no , as corresponds a trivial zero (i.e. ). Thus there are only nontrivial zeros, whose arguments are symmetric with respect to . When even, for , i.e. , which corresponds the original .
Taking the roots , i.e. , we have and re-arrange the ordering of these roots as
Comparing (3.7) and (3,8) we see that for fixing , the maximum of these roots is , thus the radius of circle satisfies , i.e. we should confine .
For , we have the following conclusions:
1) The real part has m zeros , and the imaginary part has zeros . Due to
obviously . Hence all zeros of (3.7) and (3.8) are alternatively arranged.
2) At zeros of , the peak values alternatively change their signs. At zeros of , the peak values also alternatively change their signs.
3) Because at zero of and at zero of , they all are single peak. Thus in the m root-intervals of , all form local peak-valley structures, and RH locally holds.
Finally, in with suitably small we discuss a general case
The actual zeros of are small perturbations of these zeros mentioned above, which do not change these m peak-valley structures in . When increases, they will continue to develop toward locally convex direction by
Figure 3. at zero point bifurcate into 2 or 3 zeros.
theorem 1, so RC holds. Hence theorem 2 is proved.
Numerical experiments 2. With the suggestion of Dr.XM Jiao, we have computed at the second zero of . We see in Figure 3 for , indeed bifurcate into m curves of single peak, and are alternative oscillation. The peak of develops toward its convex direction.
Remark 2. The author of this paper should sincerely thank Dr. Xiangmin Jiao (Stone Brook University, US). He, on 22 April in 2021, sent e-mail to me to discuss the highest super-convergence (see  ), we know for the first time. I told him I’m studying RC, and brings special interests and discuss together. He has carefully verified my papers and proposed valuable comments. He suggested the example and sent papers   to me. If no support from him, I very hard, at least in a shorter time, propose the newest proof.
The author expresses sincere gratitude to the reviewer for his careful remark, valuable and constructive comments. Besides, I should thank Prof. Zhengtin Hou and Prof. Xinwen Jiang for their precious opinion in discussion.
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