English

Erd\H{o}s-Burgess constant of commutative semigroups

Combinatorics 2020-05-19 v8 Number Theory

Abstract

Let S\mathcal{S} be a nonempty commutative semigroup written additively. An element ee of S\mathcal{S} is said to be idempotent if e+e=ee+e=e. The Erd\H{o}s-Burgess constant of the semigroup S\mathcal{S} is defined as the smallest positive integer \ell such that any S\mathcal{S}-valued sequence TT of length \ell contain a nonempty subsequence the sum of whose terms is an idempotent of S\mathcal{S}. We make a study of I(S){\rm I}(\mathcal{S}) when S\mathcal{S} is a direct product of arbitrarily many of cyclic semigroups. We give the necessary and sufficient conditions such that I(S){\rm I}(\mathcal{S}) is finite, and in particular, we obtain sharp bounds of I(S){\rm I}(\mathcal{S}) in case I(S){\rm I}(\mathcal{S}) is finite, and determine the precise values of I(S){\rm I}(\mathcal{S}) in some cases which unifies some well known results on the precise values of Davenport constant in the setting of commutative semigroups.

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Cite

@article{arxiv.1802.08791,
  title  = {Erd\H{o}s-Burgess constant of commutative semigroups},
  author = {Guoqing Wang},
  journal= {arXiv preprint arXiv:1802.08791},
  year   = {2020}
}

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17 pages