From: https://oyc.yale.edu/economics/econ-159

Lecture 1: First Five Lessons

Strictly dominate: Strategy alpha strictly dominates strategy beta when the payoff from alpha is strictly greater than that of beta regardless of what others do.

Lesson 1: Never play a strictly dominated game. Lesson 2: Rational play can lead to bad outcomes. Lesson 3: To decide what action to choose, figure out what your payoffs are and what the payoffs of the other players are. Lesson 4: Put yourself in your opponent’s shoes. Lesson 5: Yale students are evil :).

My prediction for the last game: 18. Rationale: You should always be 2/3 of everybody else. But everyone knows that you’ll try to be 2/3 of them, so they’ll go down by a third as well. I think most people will do this 2-3 times and then stop once they’re satisfied that they’re ahead of everyone else.

Lecture 2: Putting Yourself into Other People’s Shoes

Weakly dominate: strategy a weakly dominates b if no matter what others choose, (the payoffs from a() >= (the payoffs from b), and a > b at least once.

Common Knowledge: “I know that you know that I know that you know”… forever.

Lesson 6 (Not a real lesson) : Don’t underestimate the rationality of Yale students :). They went down a lot further than I thought they would.

Ingredients of a game:

  • players
  • strategies
  • payoffs

Notation:

  • players: i
  • strategies:
    • Set of all possible strategies of player i: S (subscript)i
    • A particular strategy of player i: s (subscript)i
    • A particular play of the game: s
  • payoffs:
    • U (subscript)i