(i) Are there limits on how many numbers must be in the set? { 1, 2 } or { 1, 5, 7, 8 , 9}
(ii) Are there limitations on how diverse or similar the numbers in the set can be? Coprime? Pairwise? { 1, 3, 9, 81 } (essentially powers of 3)
(iii) Is there any limitations on the relationship between the numbers of the set and the size of the knapsack?
(iv) If I were to make my own knapsack problem what strict criteria must I follow? For instance, is a knapsack of 3, and the set {1, 5, 6, 2} a legitimate knapsack problem? Meaning this example has the complexity class NP-Complete?