Erdös-Ko-Rado theorem with conditions on the maximal degree

نویسنده

  • Peter Frankl
چکیده

A family 9 of distinct k-element subsets of the n-element set X is called intersecting if Fn F’ # @ holds for all F, F’ E 9. Erdos, Ko, and Rado proved that for n > 2k necessarily ) 9 ) < (1: :) holds, which is clearly best possible (take all k-sets through a fixed element). For a family 9, its maximum degree d(9) is the maximum number of sets in .P= containing any particular element of X. For 3 < i< k + 1 define intersecting families 6 as follows, Let x $ ZE (;Xi) and set g = {FE($): XEF, FnZ#@}u{FE(f): x$F, ZcF}. The main result of the present paper is: if ac (c) is intersecting, d(B)2k, then 1916 /&I; holds.

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عنوان ژورنال:
  • J. Comb. Theory, Ser. A

دوره 46  شماره 

صفحات  -

تاریخ انتشار 1987