Superadditive coalitional game ($v(S\cup T)\ge v(S)+v(T)(S\cap T=\varnothing )$)

The characteristic function of a coalitional game is superadditive when disjoint coalitions can attain at least the sum of their separate values by joining. This follows when their separate strategies can be played together without interference. Superadditivity is an additional property of an abstract transferable utility game, not a consequence of merely assigning values to subsets: $v(\{1\})=v(\{2\})=v(\{1,2\})=1$ is a normalized counterexample.