From Numbers to Asymptotic Summation
How did mathematicians bridge the gap
between simple sums and the powerful tools of modern analysis?
In the early days of calculus,
mathematicians like Pierre de Fermat and Johann Faulhaber tackled the challenge
of summing powers of integers—a problem that would eventually lead to the
development of integral calculus. Their work laid the groundwork for what we
now call Riemann sums, the method of approximating areas under curves by
summing up rectangles. This approach not only helped define the integral but
also connected discrete mathematics with continuous analysis.
But the story doesn’t end there.
Jacob Bernoulli discovered that these sums could be expressed using special
numbers—now known as Bernoulli numbers—and polynomials that bear his
name. These Bernoulli numbers and polynomials appear everywhere in number
theory and combinatorics, and they even have their own beautiful symmetry
properties.
Euler-Maclaurin formula is a bridge
between sums and integrals that introduces correction terms involving Bernoulli
numbers. This formula is a cornerstone of asymptotic analysis, allowing
mathematicians to approximate sums with remarkable precision and to understand
the behavior of functions as their arguments grow large.
Mathematicians often downplay the
importance of the Euler-Maclaurin formula in textbooks—mentioning, for example,
the trapezoidal rule without explaining its deeper origins. Authors typically introduce these formulas as practical tools for
approximating integrals, but rarely emphasize that such rules are direct
consequences of the Euler-Maclaurin formula—a powerful bridge between discrete
sums and continuous integrals. This tendency to compartmentalize techniques can
obscure the unity and elegance of mathematical analysis, leaving readers
unaware of the profound connections that underpin even the simplest
computational recipes.
You’ll find a detailed and insightful
exploration of Bernoulli numbers, summation formulas and techniques in my book,
“The Riemann Hypothesis Revealed,” specifically in the section titled: “A Path from Numbers to
Asymptotic Summation”.
Why does this matter?
Because these techniques—born from
the need to sum simple powers—are now essential tools in analytic number
theory, the study of the Riemann zeta function, and the quest to understand the
distribution of prime numbers.
If you’ve ever wondered how
mathematicians turn the infinite into the manageable, or how the humble sum
connects to the deepest mysteries of mathematics, this is the path that leads
there.
Let the exploration begin.
Stirling’s formula from Euler–Maclaurin (the canonical
asymptotic bridge)
We start from the most innocent discrete object:
Apply Euler–Maclaurin to
You get
Since
this becomes
Then regrouping the constant terms gives
Set
In the limit
So
As established in my book “The Riemann Hypothesis Revealed”
Hence
Therefore,
or
This is not just “Stirling’s formula”
it is a full asymptotic expansion whose coefficients are precisely
Bernoulli numbers.
Why is this interesting for our theme?
Because the discrete object is turned into
- plus a purely arithmetic correction series.
This is probably the cleanest
historical example of: Euler–Maclaurin as a machine for asymptotic summation.
The harmonic numbers and the
appearance of
Take
Apply Euler–Maclaurin to .
You obtain
Again set
It is well known that
Subtract from
Take the limit and immediately the
result is
.
Thus,
Using the identity (as detailed in “The Riemann Hypothesis Revealed”)
the expansion becomes
So:
- Euler–Maclaurin produces Bernoulli numbers,
- analytic number theory rewrites them as
special values of the zeta function.
This is exactly where asymptotic
summation meets the analytic continuation of ζ(s).
It is one of the first places where
the zeta function is forced into an apparently elementary sum.
Epilogue to Episode 12
Episode 12 explores the development from basic summation
formulas to the Euler–Maclaurin formula, as presented in the section “A Path from
Numbers to Asymptotic Summation” of the book: ”The Riemann Hypothesis Revealed.” It demonstrates how analytic techniques connect
discrete sums with continuous integrals, providing a unified perspective on
classical and modern mathematical analysis.
By examining the role of
Bernoulli numbers and the emergence of asymptotic expansions, the episode
clarified how classical tools like Euler–Maclaurin underpin results such as
Stirling’s formula and the asymptotics of harmonic numbers. These methods are
not just theoretical curiosities—they remain central in analytic number theory
and the study of special functions, including the Riemann zeta function.
The main takeaway is that the bridge between sums and integrals,
built by mathematicians over centuries, is both practical and conceptually
unifying. The techniques discussed provide a reliable framework for
approximating sums, understanding growth rates, and connecting discrete and
continuous mathematics. For readers interested in deeper details or further
examples, the referenced book offers a more comprehensive treatment of these
ideas.
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