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In mathematics, Freiman's theorem is a combinatorial result in additive number theory. In a sense it accounts for the approximate structure of sets of integers that contain a high proportion of their internal sums, taken two at a time. The formal statement is: Let ''A'' be a finite set of integers such that the sumset : is small, in the sense that : for some constant . There exists an ''n''-dimensional arithmetic progression of length : that contains ''A'', and such that ''c and ''n'' depend only on ''c''.〔Nathanson (1996) p.251〕 A simple instructive case is the following. We always have : with equality precisely when ''A'' is an arithmetic progression. This result is due to Gregory Freiman (1964,1966).〔Nathanson (1996) p.252〕 Much interest in it, and applications, stemmed from a new proof by Imre Z. Ruzsa (1994). ==See also== *Markov spectrum 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Freiman's theorem」の詳細全文を読む スポンサード リンク
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