Sharp estimates for the M{o}bius function with coprimality restrictions.

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Title: Sharp estimates for the M{o}bius function with coprimality restrictions.
Authors: de Camargo, André Pierro1 (AUTHOR)
Source: Mathematics of Computation. Sep2026, Vol. 95 Issue 361, p2515-2538. 24p.
Subjects: Möbius function, Arithmetic functions, Mathematical constants, Number theory, Addition (Mathematics)
Abstract: We prove that, for x > q (x real), uniformly in q \geq 2, \begin{equation*} \frac {\varphi (q)}{q}\bigg |\sum _{\substack {j \leq x \\ (j,q) = 1}} \frac {\mu (j)}{j}\bigg | \log (x/q) \leq 0.3055. \end{equation*} The constant 0.3055 is optimal up to the third decimal place. This answers a question of Ramaré [Math. Comp. 84 (2015), pp. 1359–1387]. Sharper results are obtained for larger integers q. Similar results are obtained for the sums \displaystyle \sum _{\substack {j \leq x \\ (j,q) = 1}} \mu (j). [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:We prove that, for x > q (x real), uniformly in q \geq 2, \begin{equation*} \frac {\varphi (q)}{q}\bigg |\sum _{\substack {j \leq x \\ (j,q) = 1}} \frac {\mu (j)}{j}\bigg | \log (x/q) \leq 0.3055. \end{equation*} The constant 0.3055 is optimal up to the third decimal place. This answers a question of Ramaré [Math. Comp. 84 (2015), pp. 1359–1387]. Sharper results are obtained for larger integers q. Similar results are obtained for the sums \displaystyle \sum _{\substack {j \leq x \\ (j,q) = 1}} \mu (j). [ABSTRACT FROM AUTHOR]
ISSN:00255718
DOI:10.1090/mcom/4128