# FUNCTION

# Public

# FIND-NASH-EQUILIBRIUM (PAYOFF &KEY (N-ITERATIONS 100))

Find a Nash equilibrium and for a zero-sum game represented by
PAYOFF matrix (a 2d matrix or a nested list). PAYOFF is from the point
of view of the row player: the player who choses column wants to
minimize, the row player wants to maximize. The first value returned
is a vector of unnormalized probabilities assigned to each action of
the row player, the second value is the same for the column player and
the third is the expected payoff of the row player in the nash
equilibrium represented by the oddment vectors.

# Private

# EXTREMUM (VECTOR PRED &KEY (START 0) (END (LENGTH VECTOR)))

Find the first extreme value of the [START,END) subsequence of
VECTOR and return it along with its index. The extremum is what would
be the first element of VECTOR sorted by SORT with PRED.