Kneser's theorem (combinatorics): Difference between revisions

Content deleted Content added
The statement holds trivially when G is the trivial group.
The theorem is true for infinite groups G (many nice applications are when G is the group of integers).
Line 1:
In mathematics, '''Kneser's theorem''' is an [[Inequality (mathematics)|inequality]] among the sizes of certain [[sumset]]s in [[finite abelian group]]s. It belongs to the field of [[additive combinatorics]], and is named after [[Martin Kneser]], who published it in 1953.<ref>{{cite journal | first=Martin | last=Kneser | title=Abschätzungen der asymptotischen Dichte von Summenmengen | language=German | journal=[[Math. Zeitschr.]] | volume=58 | year=1953 | pages=459–484 | zbl=0051.28104 }}
</ref> It may be regarded as an extension of the [[Cauchy–Davenport theorem]], which also concerns sumsets in groups but is restricted to groups whose [[Order (group theory)|order]] is a [[prime number]].<ref name=GR143>Geroldinger & Rusza (2009) p.143</ref>