= Exponential polynomial
{title2=$F(z)=\sum_jP_j(z)e^{\lambda_jz}$}
An <exponential polynomial> is a finite sum of <polynomial> multiples of exponentials. For distinct exponents, its terms are linearly independent over the <polynomial> ring: to isolate one term, apply the product of operators $(D-\lambda_j)^{\deg P_j+1}$ for all the other terms. On the remaining <polynomial> each operator becomes $D+\lambda_0-\lambda_j$, which is injective because its nonzero constant preserves the leading coefficient. A nonzero <exponential polynomial> is an <entire function> of exponential type. Its maximum-modulus <logarithm> is $O(R+\log R)$, and <Jensen's formula> gives at most $O(R)$ zeros, counted with multiplicity, in a disk of radius $R$.
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