# Number of distinct diagrams.

1. Aug 7, 2008

### whynothis

I was just trying to think of a simple relation to find the number of distinct diagrams to a given order within a theory (specifically I am thinking of a $$\phi^{4}$$ scalar theory). I am reading Tony Zee's book and am working through his "baby problem" where he expands the integral:

$$\int_{-\inf}^{\inf} dq e^{-\frac{1}{2}m^{2}q^{2}+Jq-\frac{\lambda}{4!}q^{4}$$

in both in powers of $$\lambda$$ and J so that we can pick out diagrams to a specific order in both.

So is there a way to find the total number of distinct diagrams to order $$(\lambda^{n},J^{m})$$?

2. Jan 4, 2011

### zeion

to be honest, i have no idea.

3. Jan 5, 2011

### K^2

From personal experience, you just keep working these out by hand until you see a pattern. Or you get to a point where you give up. If there is a better way, I have not found it.