English
For arithmetic functions f and g, the L-series of their Dirichlet convolution is summable whenever both L-series are summable.
Русский
Для арифметических функций f и g сумма L‑серии свёртки существует, когда обе L‑серии суммируемы.
LaTeX
$$$LSeriesSummable (\uparrow f) s \land LSeriesSummable (\uparrow g) s \Rightarrow LSeriesSummable (\uparrow (f * g)) s$$$
Lean4
/-- The L-series of the (convolution) product of two `ℂ`-valued arithmetic functions `f` and `g`
is summable when both L-series are summable. -/
theorem LSeriesSummable_mul {f g : ArithmeticFunction ℂ} {s : ℂ} (hf : LSeriesSummable (↗f) s)
(hg : LSeriesSummable (↗g) s) : LSeriesSummable (↗(f * g)) s :=
coe_mul f g ▸ hf.convolution hg