Lambert summation

In mathematical analysis and analytic number theory, Lambert summation is a summability method for summing infinite series related to Lambert series specially relevant in analytic number theory.

Define the Lambert kernel by

( x ) = log ⁡ ( 1

/

Note that

is decreasing as a function of

A sum

is Lambert summable to

lim

, written

Abelian theorem: If a series is convergent to

then it is Lambert summable to

Tauberian theorem: Suppose that

is Lambert summable to

Then it is Abel summable to

is Lambert summable to

converges to

The Tauberian theorem was first proven by G. H. Hardy and John Edensor Littlewood but was not independent of number theory, in fact they used a number-theoretic estimate which is somewhat stronger than the prime number theorem itself.

The unsatisfactory situation around the Lambert Tauberian theorem was resolved by Norbert Wiener.

This mathematical analysis–related article is a stub.

You can help Wikipedia by expanding it.