Nevanlinna integrated counting function ($N(r,f)=n(0,f)\log r+{\int }_0^r\frac{n(t,f)-n(0,f)}{t}dt$)

The number $n(t,f)$ counts poles in $|z|<t$ with multiplicity, and $n(0,f)$ is the pole order at zero. Thus $N(r,f)=n(0,f)\log r+{\sum }_{0<|p|<r}\log (r/|p|)$. Applying this to $1/(f-a)$ counts occurrences of the value $a$.

The truncated counting function counts each distinct $a$-point of a meromorphic function once, rather than with its local multiplicity. It uses the same logarithmic radial weights as the Nevanlinna integrated counting function, including an origin contribution $\log r$ when appropriate. The difference $N-\overline{N}$ measures integrated excess multiplicity.