Let be integers and a family of -subsets of . We call intersecting if for all , and we call nontrivial if . Strengthening the famous Erdős–Ko–Rado theorem, Hilton and Milner proved that if is nontrivial and intersecting. We provide a proof by injection of this result.
"A simple proof of the Hilton–Milner theorem." Mosc. J. Comb. Number Theory 8 (2) 97 - 101, 2019. https://doi.org/10.2140/moscow.2019.8.97