Krugman on economics in 24/7

"These are 24 seconds of impenetrable jargon, followed by a 7-word explanation of your field.

24:

Given decentralized constrained optimization by maximizing agents with well-defined convex objective functions and/or convex production functions, engaging in exchange and production with free disposal, leads, in the absence of externalities, market power, and other distortions, there exists an equilibrium characterized by Pareto optimality.

7:
Greedy people, competing, make the world go round."