- A set of available customers $c_1, c_2, \dots, c_n$.
- A set of available foods $f_1, f_2, \dots, f_m$.
- Each customer will choose a subset of the available food.
- Find the maximum number of customers that can be chosen, such that no two customers share the same food.
- How to reduce the independent set problem to this problem, in order to prove that this is an NP-Complete problem ?