K subset
A k-subset of a set \(S\) is a subset of \(S\) with cardinality \(k\).
Example: The \(3\)-subset of \(S = \{1, 2, 3, 4\}\) are
\[
\{1, 2, 3\}, \{1, 2, 4\}, \{1, 3, 4\}, \{2, 3, 4\}
\]
A k-subset of a set \(S\) is a subset of \(S\) with cardinality \(k\).
Example: The \(3\)-subset of \(S = \{1, 2, 3, 4\}\) are