• Title/Summary/Keyword: pigeonhole principle

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SOME REMARKS ON SUMSETS AND RESTRICTED SUMSETS

  • Tang, Min;Wang, Wenhui
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.3
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    • pp.667-673
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    • 2019
  • Let A be a finite set of integers. For any integer $h{\geq}1$, let h-fold sumset hA be the set of all sums of h elements of A and let h-fold restricted sumset $h^{\wedge}A$ be the set of all sums of h distinct elements of A. In this paper, we give a survey of problems and results on sumsets and restricted sumsets of a finite integer set. In details, we give the best lower bound for the cardinality of restricted sumsets $2^{\wedge}A$ and $3^{\wedge}A$ and also discuss the cardinality of restricted sumset $h^{\wedge}A$.

NOTE ON THE PINNED DISTANCE PROBLEM OVER FINITE FIELDS

  • Koh, Doowon
    • Journal of the Chungcheong Mathematical Society
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    • v.35 no.3
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    • pp.227-234
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    • 2022
  • Let 𝔽q be a finite field with odd q elements. In this article, we prove that if E ⊆ 𝔽dq, d ≥ 2, and |E| ≥ q, then there exists a set Y ⊆ 𝔽dq with |Y| ~ qd such that for all y ∈ Y, the number of distances between the point y and the set E is ~ q. As a corollary, we obtain that for each set E ⊆ 𝔽dq with |E| ≥ q, there exists a set Y ⊆ 𝔽dq with |Y| ~ qd so that any set E ∪ {y} with y ∈ Y determines a positive proportion of all possible distances. The averaging argument and the pigeonhole principle play a crucial role in proving our results.