1

Part of 2016 Kurschak Competition

Problems(1)

k-element subsets with strict relation

Source: Kürschák 2016, problem 1

1\le k\le n

be integers. At most how many

k

-element subsets can we select from

\{1,2,\dots,n\}

such that for any two selected subsets, one of the subsets consists of the

k

smallest elements of their union?

combinatoricsSubsets