Peace Science explores the conditions under which cooperation, as opposed to competition, between actors can lead to the peaceful resolution of problems between individuals, communities, nations, regional entities and non-governmental organizations. Scholars working in Peace Science typically borrow theories and methods from other social sciences including catastrophe theory, chaos theory, decision science, game theory, and coalition and bargaining theory. Peace Economics is an important subfield of Peace Science, which addresses the subject from a purely economic point of view; for example, the macroeconomic impacts of reduced military expenditure. Research in Peace Economics uses several approaches, including macroeconomic stability analysis, modern growth theory, econometric models, the computable general equilibrium model (CGE), and the Richardsonian model of action and reaction in military expenditure, among others.