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Mangoldt Summatory Function


MangoldtSummatory

The Mangoldt summatory function, illustrated above, is a summatory function defined by

 psi(x)=sum_(n<=x)Lambda(n),
(1)

where Lambda(n) is the Mangoldt function. It is also called the second Chebyshev function (Edwards 2001, p. 51).

For x>1 not equal to a prime or prime power, it is given by the explicit formula

 psi(x)=x-sum_(rho)(x^rho)/rho-ln(2pi)-1/2ln(1-x^(-2)),
(2)

where the sum is over the nontrivial zeros rho of the Riemann zeta function zeta(s), i.e., those in the critical strip so 0<Re[rho]<1 (Montgomery 2001), and is interpreted as

 lim_(t->infty)sum_(|Im(rho)|<t)(x^rho)/rho.
(3)

Vallée Poussin's version of the prime number theorem states that

 psi(x)=x+O(xe^(-asqrt(lnx)))
(4)

for some a (Davenport 1980, Vardi 1991). The prime number theorem is equivalent to the statement

 psi(x)=x+o(x)
(5)

as x->infty (Dusart 1999), or equivalently

 psi(x)∼x.
(6)

Von Mangoldt rigorously derived the explicit formula in 1895, roughly three decades after the 1859 paper of Riemann that inspired it. The formula subsequently played a central role in proofs of the prime number theorem, whose equivalent formulation above is psi(x)∼x (Edwards 2001, pp. 49-54).

The Riemann hypothesis is equivalent to the estimate

 psi(x)=x+O(sqrt(x)(lnx)^2)
(7)

(Davenport 1980, p. 114; Vardi 1991).

Vardi (1991, p. 155) also gives the formula

 ln(|_x_|!)=psi(x)+psi(1/2x)+psi(1/3x)+...,
(8)

where |_x_| is the floor function and n! is a factorial.


See also

Chebyshev Functions, Explicit Formula, Mangoldt Function, Prime Number Theorem, Riemann Hypothesis, Summatory Function

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References

Costa Pereira, N. "Estimates for the Chebyshev Function psi(x)-theta(x)." Math. Comput. 44, 211-221, 1985.Costa Pereira, N. "Corrigendum: Estimates for the Chebyshev Function psi(x)-theta(x)." Math. Comput. 48, 447, 1987.Costa Pereira, N. "Elementary Estimates for the Chebyshev Function psi(x) and for the Möbius Function M(x)." Acta Arith. 52, 307-337, 1989.Davenport, H. Multiplicative Number Theory, 2nd ed. New York: Springer-Verlag, p. 114, 1980.Dusart, P. "Inégalités explicites pour psi(X), theta(X), pi(X) et les nombres premiers." C. R. Math. Rep. Acad. Sci. Canad 21, 53-59, 1999.Edwards, H. M. "Derivation of von Mangoldt's Formula for psi(x)." §3.2 in Riemann's Zeta Function. New York: Dover, pp. 49-54, 2001.Montgomery, H. L. "Harmonic Analysis as Found in Analytic Number Theory." In Twentieth Century Harmonic Analysis--A Celebration. Proceedings of the NATO Advanced Study Institute Held in Il Ciocco, July 2-15, 2000 (Ed. J. S. Byrnes). Dordrecht, Netherlands: Kluwer, pp. 271-293, 2001.Rosser, J. B. and Schoenfeld, L. "Sharper Bounds for Chebyshev Functions theta(x) and psi(x)." Math. Comput. 29, 243-269, 1975.Schoenfeld, L. "Sharper Bounds for Chebyshev Functions theta(x) and psi(x). II." Math. Comput. 30, 337-360, 1976.Vardi, I. Computational Recreations in Mathematica. Reading, MA: Addison-Wesley, pp. 146-147 and 152-155, 1991.

Cite this as:

Weisstein, Eric W. "Mangoldt Summatory Function." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/MangoldtSummatoryFunction.html

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