The Möbius Function on Abelian Semigroups
Funkcionalʹnyj analiz i ego priloženiâ, Tome 45 (2011) no. 1, pp. 88-93
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Let $X$ be an Abelian semigroup such that the following conditions hold: (i) if $x\times y=1\mspace{-4.85mu}{\mathrm I}$ ($1\mspace{-4.85mu}{\mathrm I}$ is the identity element), then $x=y=1\mspace{-4.85mu}{\mathrm I}$; (ii) the set $\{\{x,y\}\colon x\times y=a\}$ is finite for any $a\in X$. Let $\Lambda$ be any field, and let $\mathcal{E}$ be the algebra of all $\Lambda$-valued functions on $X$. The convolution of $u,v\in\mathcal{E}$ is defined by $$ (u*v)(x)=\sum\{u(a)v(b)\colon a\times b=x\}. $$ We set $\varepsilon(x)=1_{\Lambda}$ for all $x\in X$. The Möbius function $\mu$ is defined as the solution of the equation $\varepsilon*\mu=\delta$ ($\delta$ is the Dirac function). The Möbius function is unique (if it exists at all). Some existence conditions are given. If $\Lambda$ is replaced by the ring of integers, then $\mu$ exists if and only if $X$ does not contain nontrivial idempotents.
Keywords:
Abelian semigroup, free module, $\zeta$-functions.
@article{FAA_2011_45_1_a8,
author = {E. A. Gorin},
title = {The {M\"obius} {Function} on {Abelian} {Semigroups}},
journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
pages = {88--93},
year = {2011},
volume = {45},
number = {1},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/FAA_2011_45_1_a8/}
}
E. A. Gorin. The Möbius Function on Abelian Semigroups. Funkcionalʹnyj analiz i ego priloženiâ, Tome 45 (2011) no. 1, pp. 88-93. http://geodesic.mathdoc.fr/item/FAA_2011_45_1_a8/
[1] M. Kholl, Kombinatorika, Mir, M., 1970 | MR
[2] Zh. Lalleman, Polugruppy i kombinatornye prilozheniya, Mir, M., 1985 | MR
[3] E. A. Gorin, “Formuly obrascheniya Chebysheva–Mëbiusa v kontekste abelevykh polugrupp”, IV Mezhdunarodnaya konferentsiya po teorii chisel i pril. (Tula, 2001), Tezisy dokl., Izd-vo MGU, 2001, 48–49
[4] A. Klifford, G. Preston, Algebraicheskaya teoriya polugrupp, v. I, Mir, M., 1972 | Zbl