Consumer and Producer surplus

As we can see in the video the concept of consumer and producer surplus. In case of market failure
 ( monopoly) the price P is not at the point where the demand and supply curves intersect instead it is at the point much higher. Leading to the dead weight loss.

Nash equilibrium: Mixed strategy

When a player has N different strategies. A pure strategy for this player is a probability distribution over his pure strategies that is its probability vector ( P¹, .....P^N) for N strategies where the sum of all the probablity is 1

Nash equilibrium: Pure strategy

When the strategy of player 1 is not effected by the choice of player 2 nomatter what option player 2 opts for. Vise versa for player 2. This is know as pure strategy since the both players choice is not effected by other players strategy.