👉 In mathematics, a subadditive function is a real-valued function that is always positive and does not change sign under addition. This means that if f(x) ≥ g(x), then f(x + h) ≥ g(x + h) for all x in the domain of f and h in the domain of g. For example, the function f(x) = 1/x is a subadditive function because it always increases as x increases. Similarly, the function g(x) =