Definition:Rank of Entire Function

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Definition

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

Let $\sequence {a_n}$ be the sequence of non-zero zeroes of $f$, repeated according to multiplicity.


The rank of $f$ is:

the smallest positive integer $p \ge 0$ for which the series $\ds \sum_{n \mathop = 1}^\infty \size {a_n}^{-p - 1}$ converges

or:

$\infty$ if there is no such integer.


If $f$ has finitely many zeroes, its rank is $0$.


Also see


Sources