# Strange definition of regularization of Operators

1. Jun 17, 2008

### mhill

surfing the web and arxiv i found the strange formula

$$lnA= \frac{d^{n}}{ds^{n}} \frac{s^{n-1}}{n! A^{s}}$$

my question is .. where does this formula come from ??

here 'n' is supposed to be a finite parameter we must define to avoid the divergences, is it valid for non-renormalizable or renormalizable theories ??

2. Jun 17, 2008

### ZapperZ

Staff Emeritus
Whenever you want to do something like this, you must make a full citation of the source to put this into a proper context. Or else this may not make any sense.

Zz.

3. Jun 17, 2008

### mhill

4. Jun 17, 2008

### lbrits

The $$-\lim_{s\to 0}$$ out in front is important.

5. Jun 17, 2008

### lbrits

Formally taking a derivative wrt to $$A$$ on both sides should prove the identity to you.