what are the ingredients of a game ?

  1. players: i, j

  2. strategies: si

                    Si - to be sets of alternatives

                    little s to mean a particular play of the game

  3. payoffs: u  ui

                   s-i ,this is a choice for all expect person i or player i.

Definition: player i's strategy  s'i  is weakly dominated by her strategy si.

               ui(si,s-i) >= ui(s'i,s-i)          Suitable for all situations

               ui(si,s-i)  >  ui(s'i,s-i)          Suitable for any situations