Numerical Calculations to Grasp a Mathematical Issue Such As the Riemann Hypothesis
Total Page:16
File Type:pdf, Size:1020Kb
information Article Numerical Calculations to Grasp a Mathematical Issue Such as the Riemann Hypothesis Michel Riguidel Department of Computer Science and Networks, Télécom ParisTech, 75015 Paris, France; [email protected]; Tel.: +33-67687-5199 Received: 3 April 2020; Accepted: 23 April 2020; Published: 26 April 2020 Abstract: This article presents the use of data processing to apprehend mathematical questions such as the Riemann Hypothesis (RH) by numerical calculation. Calculations are performed alongside graphs of the argument of the complex numbers ζ(x + iy) = a + ib and ξ(x + iy) = p + iq, in the 1 critical strip. On the one hand, the two-dimensional surface angle tan− (b/a) of the Riemann Zeta y y function ζ is related to the semi-angle of the fractional part of 2π ln 2πe and, on the other hand, the Ksi function ξ of the Riemann functional equation is analyzed with respect to the coordinates (x, 1 x; y). − The computation of the power series expansion of the ξ function with its symmetry analysis highlights the RH by the underlying ratio of Gamma functions inside the ξ formula. The ξ power series beside the angle of both surfaces of the ζ function enables to exhibit a Bézout identity au + bv c between ≡ the components (a, b) of the ζ function, which illustrates the RH. The geometric transformations in complex space of the Zeta and Ksi functions, illustrated graphically, as well as series expansions, calculated by computer, make it possible to elucidate this mathematical problem numerically. A final theoretical outlook gives deeper insights on the functional equation’s mechanisms, by adopting a computer–scientific perspective. Keywords: Riemann Hypothesis; numerical calculation; functional equation; congruence 1. Introduction This article presents the use of data processing to apprehend mathematical questions such as the Riemann Hypothesis (RH) by numerical calculation. The geometric transformations in complex space of transcendental functions, illustrated graphically, as well as series expansions, calculated by computer, make it possible to elucidate this mathematical problem numerically. The article sets out its reasoning using descriptive graphics. The mathematical calculations have been developed and checked by computer, and the graphics have been performed through extensive specific Python programs. The RH [1] (“non-trivial zeros are located exclusively on the critical line x = 1/2”) is illustrated here with mathematical notions and numerical calculations: power series expansions of the Gamma function and Ksi function of the Riemann’s functional equation, and calculations on complex numbers and angles between two surfaces or two curves. The whole study is focused in the critical strip . S The study contribution follows from the examination of the two-angle conjunction of the Zeta function and the Ksi function. On the one hand, the Zeta function has a remarkable property on the critical line: The real/imaginary ratio of the Zeta function is interpreted as the tangent of an angle. On the other hand, the Ksi function is congruent, within a homothety and a rotation, and to a remainder series, whose sum function angle is not symmetrical with respect to the critical line. On the contrary, the residual congruent series intrinsically contains this symmetry on the critical line. It is therefore essentially an angular functional constraint of the holomorphic Zeta function and of the associated Ksi function, which is at the origin of the property of the RH. This constraint enigma is contained in the Gamma functions’ ratio of the Ksi function. Information 2020, 11, 237; doi:10.3390/info11050237 www.mdpi.com/journal/information Information 2020, 11, x FOR PEER REVIEW 2 of 32 Information 2020, 11, 237 2 of 31 Ksi function, which is at the origin of the property of the RH. This constraint enigma is contained in the Gamma functions’ ratio of the Ksi function. The nine-pagenine-page article,article, in in German, German, by by B. B. Riemann Riemann [1 ],[1], is essentialis essential in thein the history history of mathematics of mathematics and isand instructive is instructive in understanding in understanding the conjecture’s the conjecture’s context. context. Historical Historical articles articles by Hadamard by Hadamard [2], Vall [2],ée PoussinVallée Poussin [3], Bohr [3], and Bohr Landau and Landau [4], Hardy [4], [ 5Hardy], and Hardy[5], and and Hardy Littlewood and Littlewood [6] allow us[6] toallow grasp us the to extentgrasp ofthe the extent question’s of the question’s difficulty. difficulty. Deligne’s demonstrationDeligne’s demonstration in 1973 [7 ,in8], 1973 via algebraic[7,8], via geometry,algebraic geometry, gives the visiongives the and vision the victorious and the pathvictorious in the path case ofin finitethe case sets. of A finite thoughtful sets. A introduction thoughtful introduction to the properties to the of theproperties Zeta function of the Zeta is the function book by is EC the Titchmarsh: book by EC 1951 Titchmarsh: edition [ 91951], 1986 edition edition [9], [ 101986]. Less edition fundamental [10]. Less booksfundamental retrace books the various retrace works the various up to theworks years up 1974to the [11 years] and 1974 1985 [11] [12 and]. A 1985 deep [12]. insight A deep of analytic insight numberof analytic theory number concepts theory and concepts methods and can method be seens incan the be 2004 seen book in the by 2004 Iwaniec book and by Kowalski Iwaniec [and13]. TheKowalski search [13]. for non-trivial The search zeros for non-trivial using the properties zeros usin ofg complexthe properties analysis of orcomplex number analysis theory is or presented number intheory historical is presented and recent in historical publications and [recent14–20]. publications [14–20]. After this introduction, Section2 2 presents presents thethe methodology,methodology, i.e.,i.e., thethe graphicgraphic andand computationalcomputational illustration strategy. Section Section 33 presentspresents preparatorypreparatory calculationscalculations thatthat areare essentialessential forfor thethe results.results. Section4 4 presents presents thethe resultsresults ofof thethe calculationscalculations byby graphicalgraphical representationsrepresentations andand powerpower expansions.expansions. Section 55 presents presents thethe discussiondiscussion onon proofproof strategies,strategies, beforebefore thethe conclusion,conclusion, wherewhere thethe resultsresults areare summarized and research roadmapsroadmaps areare presentedpresented moremore abstractly.abstractly. 2. Methods This articlearticle presentspresents aa relation relation' of of the the function functionζ(s )=()ζ=(x +(iy+) = a) +=+ib in a congruencein a congruence form au + bv c, with a and b being the real and imaginary parts of ζ(s), respectively,( ) and, u and v being form ≡ + ≡ , with and being the real and imaginary parts of , respectively, and, independentand being functionsindependent of Zeta, functions which of are Ze dependentta, which are only dependent on x and yonly. This on congruence and . This has itscongruence source in the Riemann’s functional equation ζ(s) = ξ(s)ζ(1 s)( and) the Gamma( ) function G whose variations has its source in the Riemann’s functional equation− =() 1− and the Gamma function Γ andwhose dependencies variations and are investigated.dependencies The are study investigated is based. onThe the study specificities is based of on the the Zeta specificities function, the of Ksithe functionZeta function, and the the Gamma Ksi function function, and by the analyzing Gamma them function, with respectby analyzing to the aforementionedthem with respect relations. to the Theaforementioned components arelations.and b, formed The ofcomponents ripples, cancel and each other, formed out periodically of ripples, and cancel alternately, each other and thusout causeperiodically on the criticaland alternately, line, in the and neighborhood thus cause ofon these the undulations,critical line, thein the emergence neighborhood of an additional of these zeroundulations, but, this the time, emergence common of to an both additional curves. Thezero article but, this thus time, provides common a numerical to both curves. illustration The article of the Riemannthus provides Hypothesis a numerical (RH). illustration of the Riemann Hypothesis (RH). The methodology flowflow chart is summarized inin FigureFigure1 1:: Figure 1. Methodology Flow chart of numerical calculationscalculations to grasp the RH issue. 2.1. Strategy for Discovering Fertile Domains and Sterile Domains to Zeros We try to identify, in a domain s = x + iy, s C , a function ' of the complex plane which We try to identify, in a domainD ≔{=+,∈ℂ2 }, a function of the complex plane ( ) = 2 obeys:which obeys:s ∀ ∈ ⊂ℂ∶C : ' ζ∘s ()0=0. Expressed. Expressed in inR ℝ, the, the requirement requirement is is as as follows: follows: wewe trytry toto 8 2 D ⊂ n ◦ 2 o 2 identify, in a domain M = (x, y) R a pair (u, v) of real functions in R which obeys: M identify, in a domainD ≔{=(2, ) ∈ℝ } a pair (, ) of real functions in ℝ which8 2obeys: D ⊂ R2 : (ζ(s)) u(x, y) + (ζ(s)) v(x, y) = 0. ∀ ∈< ⊂ ℝ ×∶ ℜ()×= (, )×+ ℑ()×(, ) =0. This domain is a fertile domain where it is possible to find non-trivial zeros, since (ζ(s)) = 0 This domain D is a fertile domain where it is possible to find non-trivial zeros, since< ℜ()= then entails (ζ(s)) = 0, and vice-versa. This function pair (u, v) must obey the following requirements: 0 then entails= ℑ()=0, and vice-versa. This