Repeated Prisoner's Dilemma
April of 2003

submitted strategies:

1. Since we are playing the game for many turns we need to be semi-cautious of risk
moves (cooperate moves since they can be bad if he defects). The first 2 moves
of the opponent should be c.  Subsequent moves should be played according to
tit for tat with looking at whatever opponent has done on previous moves..

2. For the prisoner's dilemma extra credit....  i want to defect on every move.

2. I would always confess. Then the worst I can do is tie my opponent.

3. Step 1. Start by cooperating.
2->n. Calculate the probability of the other player(s) cooperating based on
their past decisions.  If probability of cooperating is >= .5 then
cooperate, else do not cooperate.

4.  Betray on the first move.
Do what the opponent did on the previous move (betray if he betrayed
previously, cooperate if he cooperated previously).

5.  flip a fair coin 5 times: heads i will say nothing, tails i
will confess.  on every six time i will say nothing to insure that i say
nothing more than i confess.

6. Cooperate the first game.  After that, defect every 4th time.

7.  My strategy is use tic-for-tat.  I
would cooperate on the first meeting, and then after that I would just always
repeat my opponent's last move.  Therefore, if he defects, I will defect, and
if he cooperates, I will cooperate.

7. Start by cooperating in the first round.  After that, do whatever the other
player did the previus round.  (tit-for-tat strategy)

8. Hello, my strategy for the continuous prisoner's dilemma is to start out
cooperating for 2 rounds.  Then betray for the the same amount your opponent
betrayed you up to that point  [in the previous two rounds - LV] .Then start over [with c, c - LV].

 game from the textbook c d c -2, -2 ( bonus points: 8,8;cc=8) -10, -1 (bonus points: 0, 9;cd=0) d -1, -10 (bonus points 9,0;dc=9) -5, -5 (bonus points: 5,5;dd=5)

Results of tournament:
(each rows describes payoofs for the corresponding strategy)
 1 2  (two) 3 4 5 6 7 (two) 8 1 cc dd cc cc cc/3+cd/4+dc/4+dd/6 (2cc+cd+dc)/4 cc cc 2 dd dd dd dd (2.5dd+3.5dc)/6 (3dc+dd)/4 dd dd 3 cc dd cc (dc+cd)/2 (3.5cc+2.5cd)/6 (3cc+cd)/4 cc cc 4 cc dd (dc+cd)/2 dd cc/3+cd/4+dc/4+dd/6 (2cc+cd+dc)/4 (cd+dc)/2 (cc+cd+dc)/3 5 cc/3+cd/4+dc/4+dd/6 (2.5dd+3.5cd)/6 (3.5cc+2.5dc)/6 cc/3+cd/4+dc/4+dd/6 3cc/8+5(cd+dc+dd)/24 (5cc+2cd+4dc+dd)/12 cc/3+cd/4+dc/4+dd/6 6 (2cc+cd+dc)/4 (3cd+dd)/4 (3cc+dc)/4 (2cc+cd+dc)/4 (5cc+4cd+2dc+dd)/12 (3cc+dd)/4 (2cc+cd+dc)/4 (2cc+cd+dc)/4 7 cc dd cc (dc+cd)/2 cc/3+cd/4+dc/4+dd/6 (2cc+cd+dc)/4 cc cc 8 cc dd cc (cc+cd+dc)/3 (2cc+cd+dc)/4 cc cc

Bonus points multiplied by 10:
1. 41cc/6+ cd/2+ dc/2 + 13dd/6   =  70 .
2.   4dc/3+26dd/3=55+1/3  ~ 60.
3. 5cc+2dd+(dc+cd)/2+(3.5cc+2.5cd)/6+(3cc+cd)/4=19cc/3+7cd/6+dc/2+2dd=65+1/6  ~ 70.
4. cc+3dd+(dc+cd)+(dc+cd)/2+(2cc+cd+dc)/4+cc/3+cd/4+dc/4+dd/6+(cc+cd+dc)/3= {13 cc + 14 cd + 14 dc + 19 dd)/6=325/6  ~ 50 .
6. (2cc+cd+dc)/4+(3cd+dd)/2+(3cc+dc)/4+(3cc+dc)/4+(5cc+4cd+2dc+dd)/12+(3cc+dd)/4+(2cc+cd+dc)/2+(2cc+cd+dc)/4 =
(28cc+17cd+10dc+5dd)/6=113/2  ~ 60.
7. 5cc+2dd+(dc+cd)/2+cc/3+cd/4+dc/4+dd/6+(2cc+cd+dc)/4 =(35cc+6cd+6dc+13dd)/6=133/2 ~ 70.

Computing result of matching 5 with 8 is difficult, so I take average of 9 matches. Bonus points multiplied by 9:
5. cc/3+cd/4+dc/4+dd/6+(2.5dd+3.5cd)/3+(3.5cc+2.5dc)/6+cc/3+cd/4+dc/4+dd/6+3cc/8+5(cd+dc+dd)/24+(5cc+2cd+4dc+dd)/12+2(cc/3+cd/4+dc/4+dd/6)  ~ 45.
8. 5cc+2dd+(cc+cd+dc)/3+(2cc+cd+dc)/4  ~ 63.

% /.{cc->8,dd->5,cd->0,dc->9}
% /.{cc->1,dd->1,cd->1,dc->1}

1  c c c c d c c c d
6  c c c d c c c d c
period 4

4 d c
7 c d
period 2

3  c  d  c  d  c  d
4  d  c  d  c  d  c
period 2

4 d c c d c c
8 c c d c c d
period 3

6 c c c d c   c c d c c c d c
8 c c c c d   c c c c d c c d
period 8