On direct and inverse problems related to some dilated sumsets

Let $A$ be a nonempty finite set of integers. For a real number $m$, the set $m\cdot A=\lbrace ma: a\in A\rbrace $ denotes the set of $m$-dilates of $A$. In 2008, Bukh initiated an interesting problem of finding a lower bound for the sumset of dilated sets, i.e., a lower bound for $|\lambda _1\cdot...

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Bibliographic Details
Main Authors: Kaur, Ramandeep, Singh, Sandeep
Format: Article
Language:English
Published: Académie des sciences 2024-02-01
Series:Comptes Rendus. Mathématique
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Online Access:https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.537/
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Summary:Let $A$ be a nonempty finite set of integers. For a real number $m$, the set $m\cdot A=\lbrace ma: a\in A\rbrace $ denotes the set of $m$-dilates of $A$. In 2008, Bukh initiated an interesting problem of finding a lower bound for the sumset of dilated sets, i.e., a lower bound for $|\lambda _1\cdot A+\lambda _2\cdot A+\cdots +\lambda _h\cdot A|$, where $\lambda _1, \lambda _2, \dots , \lambda _h$ are integers and $A$ be a subset of integers. In particular, for nonempty finite subsets $A$ and $B$, the problem of dilates of $A$ and $B$ is defined as $A+k\cdot B=\lbrace a+kb:a\in A$ and $b\in B\rbrace $. In this article, we obtain the lower bound for the cardinality of $A+k\cdot B$ with $k\ge 3$ and describe sets for which equality holds. We also derive an extended inverse result with some conditions for the sumset $A+3\cdot B$.
ISSN:1778-3569