Game Development Reference
In-Depth Information
GAME THEORY DEFINITIONS
When reading about game theory, you will occasionally see references to the follow-
ing terms.
Two-person: A game played by two people. Alternatively, this can apply to
two teams of people working together toward the same goals (e.g., Bridge).
Zero-sum: A game that has a balancing end condition such as one winner and
one loser (e.g., Chess, Checkers, Tic-Tac-Toe), or whatever is gained by one
player is lost by the other player (e.g., Poker with a fixed amount of money at
the table).
Non-zero-sum: A game where there are degrees of winning and losing (e.g.,
Poker, a lottery, a contest where you get to keep your score such as Bridge).
Perfect knowledge: A game where each player sees everything that is going
on (e.g., Chess, Checkers, Tic-Tac-Toe).
Imperfect knowledge: A game where some information is hidden from the
player (e.g., Battleship, Poker, anything with a “fog of war�).
Cooperative: A game where the players can form binding commitments.
Symmetric: A game where both sides have the same information and play by
the same rules.
Asymmetric: A game where one side has different rules and/or different infor-
mation than the other.
Fourteenth-century English logician and Franciscan friar William of Occam is cred-
ited with one of the most useful notions in all of science.
Occam's razor
states,
“Entia non sunt multiplicanda praeter necessitatem.� For those of you who don't
speak Latin (I admit that I must include myself here), this roughly translates as
“entities must not be multiplied beyond necessity.� There have been plenty of
restatements of this edict that are a bit clearer. Two of the more oft-quoted are “all
other things being equal, the simplest solution is the best� and “the simplest expla-
nation that covers all the facts is usually the best.�
Brother Occam would have been pleased with John von Neumann. Despite the
fact that he was a brilliantly talented mathematician (he was famously known for
declining to use the supercomputer he actually helped invent because he could do
the calculations faster in his head), Mr. von Neumann knew when flash and style
were inappropriate. One of the useful aspects of his presentation of game theory
