Swap regret is a concept from game theory. It is a generalization of regret in a repeated, n-decision game.
Definition
A player's swap-regret is defined to be the following:
Intuitively, it is how much a player could improve by switching each occurrence of decision i to the best decision j possible in hindsight. The swap regret is always nonnegative.
Swap regret is useful for computing correlated equilibria.
References
Swap regret Wikipedia(Text) CC BY-SA