Subset sum is given by this question:The problem is this: given a set (or multiset) of integers, is there a non-empty subset whose sum is zero?My question is: If the numbers in the set are functions of other numbers, is that still subset sum? For exampleThe set {1,2,3} where the first number is X, the second is X+1, third is X+2 and so on. So it is a general set.Is this allowed? 
Constraints on subset sum problem
complexity theory;decision problem