Definition:Rank of Entire Function

Definition
Let $f: \C \to \C$ be an entire function.

Let $\left\langle{a_n}\right\rangle$ be the sequence of nonzero zeroes of $f$, repeated according to multiplicity.

The rank of $f$ is the smallest integer $\tau\geq0$ for which the series $\displaystyle\sum_{n\mathop=1}^\infty |a_n|^{-\tau-1}$ converges, or $\infty$ if there is no such integer.

Also see

 * Definition:Exponent of Convergence
 * Definition:Order of Entire Function
 * Definition:Genus of Entire Function