Sharpening the LYM inequality
نویسندگان
چکیده
More detailed information about the s t ructure of Sperner families can be obtained by considering their level sequences. The level sequence of a family 4 , f ( ~ ) = {fi(Y)}, has f i (~) equal to the number of members of ~ with exac t ly ' / e l emen t s . Sperner 's theorem asserts tha t ~fi(2~)<_ ([~j) . A stronger restriction on the level i sequence was proved independent ly by Lubell, Yamamoto and Meshalkin:
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ورودعنوان ژورنال:
- Combinatorica
دوره 12 شماره
صفحات -
تاریخ انتشار 1992