On the size of the set A(A+1)

dc.creatorGaraev, M. Z.
dc.creatorShen, Chun-Yen
dc.date2008-11-26
dc.date2008-12-16
dc.date.accessioned2026-07-07T12:12:38Z
dc.date.available2026-07-07T12:12:38Z
dc.descriptionLet $F_p$ be the field of a prime order $p.$ For a subset $A\subset F_p$ we consider the product set $A(A+1).$ This set is an image of $A\times A$ under the polynomial mapping $f(x,y)=xy+x:F_p\times F_p\to F_p.$ In the present paper we show that if $|A|<p^{1/2},$ then $$ |A(A+1)|\ge |A|^{106/105+o(1)}.$$ If $|A|>p^{2/3},$ then we prove that $$|A(A+1)|\gg \sqrt{p |A|}$$ and show that this is the optimal in general settings bound up to the implied constant. We also estimate the cardinality of $A(A+1)$ when $A$ is a subset of real numbers. We show that in this case one has the Elekes type bound $$ |A(A+1)|\gg |A|^{5/4}. $$
dc.descriptionMinor corrections
dc.identifierhttps://arxiv.org/abs/0811.4206
dc.identifierhttp://arxiv.org/abs/0811.4206
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/210608
dc.subjectNumber Theory
dc.subject11B75
dc.titleOn the size of the set A(A+1)
dc.typetext

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