= Formal integral
{title2=$I\!\left(\sum_{n\geq0}a_nx^n\right)=\sum_{n\geq0}\frac{a_n}{n+1}x^{n+1}$}
For a <formal power series> over a <field> of <characteristic zero>, the displayed coefficientwise operation chooses constant coefficient zero. Its <formal derivative> is the original <formal power series>: differentiating the term with exponent $n+1$ cancels its denominator. Conversely, formally integrating a <formal derivative> removes the original constant term. These are algebraic identities; analytic <convergence> is not required.
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