All maximum 2-part Sperner families
نویسندگان
چکیده
Let X= X, v ,I’?, X, n X2 = 0 be a partition of an n-element set. Suppose that the family % of some subsets of X satisfy the following condition: if there is an inclusion F, G Fz (F,, Fz E 5”) in %, the difference F, F, cannot be a subset of X, or ,I’>. Kleitman (Math. Z. 90 (1965), 251-259) and Katona (Sfudia Sci. Math. Hungar. 1 (1966) 59-63) proved 20 years ago that 1% 1 is at most n choose Ln/2j. We determine all families giving equality in this theorem. :(’ 1986 Academic Press, Inc.
منابع مشابه
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عنوان ژورنال:
- J. Comb. Theory, Ser. A
دوره 43 شماره
صفحات -
تاریخ انتشار 1986