Von Mangoldt function: Difference between revisions
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Matsgranvik (talk | contribs) Added section Expansion of terms |
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:<math>\sum_n c_n \lambda^{-n}\,</math> |
:<math>\sum_n c_n \lambda^{-n}\,</math> |
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can be shown to be a convergent series for <math>\lambda > 1</math>. |
can be shown to be a convergent series for <math>\lambda > 1</math>. |
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==Expansion of terms== |
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The terms of the von Mangoldt function can be expanded into series which have numerators that form a symmetric matrix starting: |
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:<math> T(n,k) = \begin{bmatrix} 1&1&1&1&1&1 \\ 1&-1&1&-1&1&-1 \\ 1&1&-2&1&1&-2 \\ 1&-1&1&-1&1&-1 \\ 1&1&1&1&-4&1 \\ 1&-1&-2&-1&1&2 \end{bmatrix} </math> |
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This matrix is defined by the recurrence: |
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:<math> T(n,1)=1,\;T(1,k)=1,\;n \geq k: -\sum\limits_{i=1}^{k-1} T(n-i,k),\;n<k: -\sum\limits_{i=1}^{n-1} T(k-i,n) </math> |
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The von Mangoldt function can then for <math> n>1 </math> be calculated as {{ref|Gra11}}: |
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:<math> \Lambda(n) = \sum\limits_{k=1}^{\infty}\frac{T(n,k)}{k} </math> |
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==See also== |
==See also== |
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* {{note|Apo76}} {{Apostol IANT}} |
* {{note|Apo76}} {{Apostol IANT}} |
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* {{note|Hard16}} {{Cite journal |first=G. H. |last=Hardy |lastauthoramp=yes |first2=J. E. |last2=Littlewood |url=http://www.ift.uni.wroc.pl/%7Emwolf/Hardy_Littlewood%20zeta.pdf |title=Contributions to the Theory of the Riemann Zeta-Function and the Theory of the Distribution of Primes |journal=Acta Mathematica |volume=41 |issue= |year=1916 |pages=119–196 |doi=10.1007/BF02422942 }} |
* {{note|Hard16}} {{Cite journal |first=G. H. |last=Hardy |lastauthoramp=yes |first2=J. E. |last2=Littlewood |url=http://www.ift.uni.wroc.pl/%7Emwolf/Hardy_Littlewood%20zeta.pdf |title=Contributions to the Theory of the Riemann Zeta-Function and the Theory of the Distribution of Primes |journal=Acta Mathematica |volume=41 |issue= |year=1916 |pages=119–196 |doi=10.1007/BF02422942 }} |
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* http://math.stackexchange.com/questions/48946/do-these-series-converge-to-the-mangoldt-function |
* {{note|Gra11}} Mats Granvik, ''[http://math.stackexchange.com/questions/48946/do-these-series-converge-to-the-mangoldt-function Do these series converge to the Mangoldt function]'' (2011) |
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== References == |
== References == |
Revision as of 11:34, 10 September 2011
In mathematics, the von Mangoldt function is an arithmetic function named after German mathematician Hans von Mangoldt.
Definition
The von Mangoldt function, conventionally written as Λ(n), is defined as
It is an example of an important arithmetic function that is neither multiplicative nor additive.
The von Mangoldt function satisfies the identity[1]
that is, the sum is taken over all integers d which divide n. This is proved by the fundamental theorem of arithmetic, since the terms that are not powers of primes are equal to 0.
- For instance, let n=12. Recall the prime factorization of 12, 12=22·3, which will turn up in the example.
- Take the summation over all distinct positive divisors d of n:
-
- This provides an example of how the summation of the von Mangoldt function equals log (n).
The summatory von Mangoldt function, ψ(x), also known as the Chebyshev function, is defined as
von Mangoldt provided a rigorous proof of an explicit formula for ψ(x) involving a sum over the non-trivial zeros of the Riemann zeta function. This was an important part of the first proof of the prime number theorem.
Dirichlet series
The von Mangoldt function plays an important role in the theory of Dirichlet series, and in particular, the Riemann zeta function. In particular, one has
for . The logarithmic derivative is then
These are special cases of a more general relation on Dirichlet series.[2] If one has
for a completely multiplicative function , and the series converges for , then
converges for .
Mellin transform
The Mellin transform of the Chebyshev function can be found by applying Perron's formula:
which holds for .
Exponential series
Hardy and Littlewood examine the series[3]
in the limit . Assuming the Riemann hypothesis, they demonstrate that
Curiously, they also show that this function is oscillatory as well, with diverging oscillations. In particular, there exists a value such that
- and
infinitely often. The graphic to the right indicates that this behaviour is not at first numerically obvious: the oscillations are not clearly seen until the series is summed in excess of 100 million terms, and are only readily visible when .
Riesz mean
The Riesz mean of the von Mangoldt function is given by
Here, and are numbers characterizing the Riesz mean. One must take . The sum over is the sum over the zeroes of the Riemann zeta function, and
can be shown to be a convergent series for .
Expansion of terms
The terms of the von Mangoldt function can be expanded into series which have numerators that form a symmetric matrix starting:
This matrix is defined by the recurrence:
The von Mangoldt function can then for be calculated as [4]:
See also
Notes
- ^ Allan Gut, Some remarks on the Riemann zeta distribution (2005)
- ^ Apostol, Tom M. (1976), Introduction to analytic number theory, Undergraduate Texts in Mathematics, New York-Heidelberg: Springer-Verlag, ISBN 978-0-387-90163-3, MR 0434929, Zbl 0335.10001
- ^ Hardy, G. H.; Littlewood, J. E. (1916). "Contributions to the Theory of the Riemann Zeta-Function and the Theory of the Distribution of Primes" (PDF). Acta Mathematica. 41: 119–196. doi:10.1007/BF02422942.
{{cite journal}}
: Unknown parameter|lastauthoramp=
ignored (|name-list-style=
suggested) (help) - ^ Mats Granvik, Do these series converge to the Mangoldt function (2011)
References
- S.A. Stepanov (2001) [1994], "Mangoldt function", Encyclopedia of Mathematics, EMS Press