# Product transformations?

1. Jul 28, 2006

### benorin

Certianly there is a lot of reference material on series transformations: they accelerate convergence, provide analytic continuations and what not. But I have not yet seen a like presentation of product transformations. Given that there are ways to write a product as a series, and vice-versa (see this post), would it be so difficult to translate known series transformations into product transformations?

An example application would be the Riemann zeta fcn, the series definition can be analytically continued to the whole complex plane (except z=1) via some clever series manipulation + a series transformation (see this post), but has anybody ever used similar techniques to analytically continue the Euler product over primes representation of the Riemann zeta? Yeah, I know about the Hadamard Product derived using the Weierstrass formula, but that is not what I'm after.

-Ben

Last edited: Jul 28, 2006
2. Jul 28, 2006

### Edwin

I would be interested in helping you research this concept, as I am interested in infinite product representations; because, one can take the argument of an infinite product term-by-term. Specifically, I am interested in infinite product representations for functions of the form:

h(z) = f(z)*g(z) - e, where e is some positive real valued constant.

To start, perhaps we could look for a way to convert Taylor series, power series, geometric series, and some other well known series into infinite product representations, or see if anyone else has come up with a way to do this. We could then see if there are ways to generalize the technique to any infinite series.

What do you think?

Does this sound feasible?

Inquisitively,

Edwin

3. Jul 28, 2006

### benorin

Edwin, you should look-up the Weierstrass Product Theorem (a.k.a. the Weierstrass Factorization Theorem) which is similar to converting Taylor series into an infinite product form, and see this post for the infinite product version of the geometric series