Swap regret

Swap regret is a concept from game theory. It is a generalization of regret in a repeated, n-decision game.

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.

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