Intersecting $k$-Uniform Families Containing all the $k$-Subsets of a Given Set
Let $m, n$, and $k$ be integers satisfying $0 < k \leq n < 2k \leq m$. A family of sets $\mathcal{F}$ is called an $(m,n,k)$-intersecting family if $\binom{[n]}{k} \subseteq \mathcal{F} \subseteq \binom{[m]}{k}$ and any pair of members of $\mathcal{F}$ have nonempty intersection. Maximum $(m,k,k)$- and $(m,k+1,k)$-intersecting families are determined by the theorems of Erdős-Ko-Rado and Hilton-Milner, respectively. We determine the maximum families for the cases $n = 2k-1, 2k-2, 2k-3$, and $m$ sufficiently large.
2017 ◽
Vol 27
(1)
◽
pp. 60-68
◽
Keyword(s):
Keyword(s):
2009 ◽
Vol 18
(1-2)
◽
pp. 107-122
◽
Keyword(s):
Keyword(s):
Keyword(s):
2012 ◽
Vol 21
(1-2)
◽
pp. 301-313
◽
Keyword(s):
2014 ◽
Vol 10
(07)
◽
pp. 1637-1647
◽
Keyword(s):