additivity A property of functions like the characteristic function in a cooperative game. This function is additive for two disjoint, or separate, coalitions when the union of the coalitions obtains exactly the sum of their separate outcomes. Additivity implies there is no synergy between the two coalitions.
adverse selection Situations in which information asymmetry leads to undesirable outcomes. The typical applications are in insurance and banking, where one party is informed of certain risks while the other is not.
anchor A prior, numerical point of comparison.
asymmetric information Occurs in games when one player knows the payoffs for both players but the other player only knows his or her own payoffs.