On page 532 of the book analytic number theory by Iwaniec and Kowalski, the following notation is used:
$C^{~\infty}$ and $\tau(n,\chi)$.
Could anyone tell me what these represent? (the former is definitely not functions!)
Thanks!
On page 532 of the book analytic number theory by Iwaniec and Kowalski, the following notation is used:
$C^{~\infty}$ and $\tau(n,\chi)$.
Could anyone tell me what these represent? (the former is definitely not functions!)
Thanks!
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$c|C^{\infty}$ just means that $c|C^k$ for large $k$.
$\tau(n,\chi)$ is a twisted divisor function $\sum_{d|n} \chi(d)$.