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Mertens Conjecture


MertensConjecture

Given the Mertens function defined by

 M(n)=sum_(k=1)^nmu(k),
(1)

where mu(n) is the Möbius function, Stieltjes claimed in an 1885 letter to Hermite that M(x)x^(-1/2) stays within two fixed bounds, which he suggested could probably be taken to be +/-1 (Havil 2003, p. 208). In the same year, Stieltjes (1885) claimed that he had a proof of the general result. However, it seems likely that Stieltjes was mistaken in this claim (Derbyshire 2004, pp. 160-161). Mertens (1897) subsequently published a paper opining based on a calculation of M(10^4) that Stieltjes' claim

 |M(x)|<x^(1/2)
(2)

for x>1 was "very probable."

The Mertens conjecture has important implications, since the truth of any equality of the form

 |M(n)|<=cn^(1/2)
(3)

for any fixed c (the form of the Mertens conjecture with c=1) would imply the Riemann hypothesis. In fact, the statement

 M(n)=O(n^(1/2+epsilon))
(4)

for any epsilon<1/2 is equivalent to the Riemann hypothesis (Derbyshire 2004, p. 251).

Mertens (1897) verified the conjecture for n<10000, and this was subsequently extended to n<500000 by von Sterneck (1912; Deléglise and Rivat 1996). The Mertens conjecture was proved false by Odlyzko and te Riele (1985). Their proof is indirect and does not produce a specific counterexample, but it does show that

limsup_(n->infty)M(n)n^(-1/2)>1.06
(5)
liminf_(n->infty)M(n)n^(-1/2)<-1.009
(6)

(Havil 2003, p. 209). Odlyzko and te Riele (1985) believe that there are no counterexamples to the Mertens conjecture for n<=10^(20), or even 10^(30), calling Stieltjes' supposed proof into very strong question (Derbyshire 2004, p. 161).

Pintz (1987) subsequently showed that at least one counterexample to the conjecture occurs for n<exp(3.21×10^(64)) (Havil 2003, p. 209), using a weighted integral average of M(x)/x and a discrete sum involving nontrivial zeros of the Riemann zeta function. The first value of n for which |M(n)|>sqrt(n) is still unknown, but it is known to exceed 10^(14) (te Riele 2006), improving the previous best results of 10^(13) (Lioen and van de Lune 1994) and 10^(12) (Dress 1993; Deléglise and Rivat 1996).

It is still not known if

 limsup_(n->infty)|M(n)|n^(-1/2)=infty,
(7)

although it seems very probable (Odlyzko and te Riele 1985).


See also

Mertens Function, Möbius Function, Riemann Hypothesis

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References

Anderson, R. J. "On the Mertens Conjecture for Cusp Forms." Mathematika 26, 236-249, 1979.Anderson, R. J. "Corrigendum: 'On the Mertens Conjecture for Cusp Forms.' " Mathematika 27, 261, 1980.Deléglise, M. and Rivat, J. "Computing the Summation of the Möbius Function." Experiment. Math. 5, 291-295, 1996.Derbyshire, J. Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics. New York: Penguin, 2004.Devlin, K. "The Mertens Conjecture." Irish Math. Soc. Bull. 17, 29-43, 1986.Dress, F. "Fonction sommatoire de la fonction de Möbius; 1. Majorations expérimentales." Experiment. Math. 2, 93-102, 1993.Grupp, F. "On the Mertens Conjecture for Cusp Forms." Mathematika 29, 213-226, 1982.Hardy, G. H. Ramanujan: Twelve Lectures on Subjects Suggested by His Life and Work, 3rd ed. New York: Chelsea, p. 64, 1999.Havil, J. Gamma: Exploring Euler's Constant. Princeton, NJ: Princeton University Press, 2003.Jurkat, W. and Peyerimhoff, A. "A Constructive Approach to Kronecker Approximation and Its Application to the Mertens Conjecture." J. reine angew. Math. 286/287, 322-340, 1976.Lehman, R. S. "On Liouville's Functions." Math. Comput. 14, 311-320, 1960.Lioen, W. M. and van de Lune, J. "Systematic Computations on Mertens' Conjecture and Dirichlet's Divisor Problem by Vectorized Sieving." In From Universal Morphisms to Megabytes: A Baayen Space Odyssey. On the Occasion of the Retirement of P. C. Baayen (Ed. K. Apt, L. Schrijver, and N. Temme). Amsterdam, Netherlands: Stichting Mathematisch Centrum, Centrum voor Wiskunde en Informatica, pp. 421-432, 1994. http://walter.lioen.com/papers/LL94.pdf.Mertens, F. "Über eine zahlentheoretische Funktion." Sitzungsber. Akad. Wiss. Wien IIa 106, 761-830, 1897.Odlyzko, A. M. and te Riele, H. J. J. "Disproof of the Mertens Conjecture." J. reine angew. Math. 357, 138-160, 1985.Pintz, J. "An Effective Disproof of the Mertens Conjecture." Astérique 147-148, 325-333 and 346, 1987.Stieltjes, T. J. "Sur une loi asymptotique dans la théorie des nombres." C. R. Acad. Sci. Paris 101, 368-370, 1885.te Riele, H. J. J. "Some Historical and Other Notes About the Mertens Conjecture and Its Recent Disproof." Nieuw Arch. Wisk. 3, 237-243, 1985.te Riele, H. R. "The Mertens Conjecture Revisited." 7th Algorithmic Number Theory Symposium. Technische Universität Berlin, 23-28 July 2006. http://www.math.tu-berlin.de/~kant/ants/Proceedings/te_riele/te_riele_talk.pdf.von Sterneck, R. D. "Die zahlentheoretische Funktion sigma(n) bis zur Grenze 500000." Akad. Wiss. Wien Math.-Natur. Kl. Sitzungsber. IIa 121, 1083-1096, 1912.

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Mertens Conjecture

Cite this as:

Weisstein, Eric W. "Mertens Conjecture." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/MertensConjecture.html

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