. capture net install http://nicolaorsini.altervista.org/stata/gamet
.
. which gamet
.\gamet.ado
*! N.Orsini, D.Rizzuto, N.Nante
*! Version 1.0 - November 4, 2004
*! Version 1.1 - November 8, 2004
*! Version 1.2 - February 19, 2005
.
. help gamet
.
. * DOMINANT AND DOMINATED STRATEGIES
.
. gamet , payoff(2, 2, 0, 1 \ 3, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(Provider) ls2(Customer) domist
----------------------------
| Customer
Provider | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (3; 0) (1; 1)
----------------------------
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Provider is High
No dominated strategy for Customer
Dominant strategy for Provider is Low
No dominant strategy for Customer
.
. * ITERATED ELIMINATION OF STRONGLY DOMINATED STRATEGIES
.
. gamet, payoff(0, 0, 12, 8, 18, 9, 36, 0\ 8, 12, 16, 16, 20, 15, 32, 0 \ 9, 18
> , 15, 20, 18, 18, 27, 0\0, 36, 0, 32, 0, 27, 0, 0) ///
> player1(H M L N) player2(h m l n) ls1(Firm_I) ls2(Firm_II) elids
--------------------------------------------------
| Firm_II
Firm_I | h m l n
----------+---------------------------------------
H | (0; 0) (12; 8) (18; 9) (36; 0)
M | (8; 12) (16; 16) (20; 15) (32; 0)
L | (9; 18) (15; 20) (18; 18) (27; 0)
N | (0; 36) (0; 32) (0; 27) (0; 0)
--------------------------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Firm_I is N
Dominated strategy for Firm_II is n
No dominant strategy for Firm_I
No dominant strategy for Firm_II
----------------------------------------
| Firm_II
Firm_I | h m l
----------+-----------------------------
H | (0; 0) (12; 8) (18; 9)
M | (8; 12) (16; 16) (20; 15)
L | (9; 18) (15; 20) (18; 18)
----------------------------------------
Iteration 2
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Firm_I is H
Dominated strategy for Firm_II is h
No dominant strategy for Firm_I
No dominant strategy for Firm_II
------------------------------
| Firm_II
Firm_I | m l
----------+-------------------
M | (16; 16) (20; 15)
L | (15; 20) (18; 18)
------------------------------
Iteration 3
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Firm_I is L
Dominated strategy for Firm_II is l
Dominant strategy for Firm_I is M
Dominant strategy for Firm_II is m
--------------------
| Firm_II
Firm_I | m
----------+---------
M | (16; 16)
--------------------
Iteration 4
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Firm_I
No dominated strategy for Firm_II
Dominant strategy for Firm_I is M
Dominant strategy for Firm_II is m
.
. * NASH EQUILIBRIM IN PURE STRATEGIES
.
. gamet , payoff(2, 2, 0, 1 \ 3, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(Provider) ls2(Customer) domist neps
----------------------------
| Customer
Provider | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (3; 0) (1; 1)
----------------------------
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Provider is High
No dominated strategy for Customer
Dominant strategy for Provider is Low
No dominant strategy for Customer
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Low Not_buy (1; 1)
.
. * NASH EQUILIBRIM IN MIXED STRATEGIES
.
. gamet , payoff(2, 2, 0, 1 \ 3, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(Provider) ls2(Customer) neps
----------------------------
| Customer
Provider | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (3; 0) (1; 1)
----------------------------
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Low Not_buy (1; 1)
.
. gamet, pay(0, 0, -10, 10 \ -1, 0, -6, -90) player1(Not_inspect Inspect) playe
> r2(Comply Cheat) ls1(I) ls2(II) nefms
----------------------------------
| II
I | Comply Cheat
------------+---------------------
Not_inspect | (0; 0) (-10; 10)
Inspect | (-1; 0) (-6; -90)
----------------------------------
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.90
q = 0.80
(0.90*[Not_inspect]+0.10*[Inspect], 0.80*[Comply]+0.20*[Cheat])
Expected equilibrium payoff for I
0.80*0+(1-0.80)*-10 = -2
0.80*-1+(1-0.80)*-6 = -2
Expected equilibrium payoff for II
0.90*0+(1-0.90)*0 = 0
0.90*10+(1-0.90)*-90 = 0
.
. * GAME TREE - BACKWARD INDUCTION
.
. gamet , payoff(2, 2, 0, 1 \ 3, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(Provider) ls2(Customer) gtree
----------------------------
| Customer
Provider | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (3; 0) (1; 1)
----------------------------
BACKWARD INDUCTION
Equilibrium path: High Buy
Payoffs pair: (2; 2)
.
. gamet, payoff(2, 2, 0, 1 \ 3, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(I) ls2(II) gtree ///
> plotregion(color(yellow)) graphregion(color(yellow)) note(Change layout as m
> uch as you like) texts(large) ///
> msizes(*12) mlabpp1(9) title(Quality choice example) subtitle(I moves first)
----------------------------
| II
I | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (3; 0) (1; 1)
----------------------------
BACKWARD INDUCTION
Equilibrium path: High Buy
Payoffs pair: (2; 2)
.
. gamet, payoff(0, 0, 12, 8, 18, 9, 36, 0\ 8, 12, 16, 16, 20, 15, 32, 0 \ 9, 18
> , 15, 20, 18, 18, 27, 0\0, 36, 0, 32, 0, 27, 0, 0) ///
> player1(H M L N) player2(h m l n) ls1(Firm_I) ls2(Firm_II) gtree title(Exten
> sive form)
--------------------------------------------------
| Firm_II
Firm_I | h m l n
----------+---------------------------------------
H | (0; 0) (12; 8) (18; 9) (36; 0)
M | (8; 12) (16; 16) (20; 15) (32; 0)
L | (9; 18) (15; 20) (18; 18) (27; 0)
N | (0; 36) (0; 32) (0; 27) (0; 0)
--------------------------------------------------
BACKWARD INDUCTION
Equilibrium path: H l
Payoffs pair: (18; 9)
.
. * MAXIMIN FOR ZERO-SUM GAME
.
. gamet, payoff(-5, 5, 3, -3, 1, -1, 20, -20\5, -5, 5, -5, 4, -4, 6, -6\ -4, 4,
> 6, -6, 0, 0, -5, 5) ///
> player1(1 2 3) player2(1 2 3 4) maximin
------------------------------------------------------
| S2
S1 | 1 2 3 4
----------+-------------------------------------------
1 | (-5; 5) (3; -3) (1; -1) (20; -20)
2 | (5; -5) (5; -5) (4; -4) (6; -6)
3 | (-4; 4) (6; -6) (0; 0) (-5; 5)
------------------------------------------------------
ZERO-SUM GAME - MAXIMIN CRITERION
Minimal Column Maximum of S1 = 4
Maximal Row Minimum of -{S2} = -4
Saddle-point = 2 3
.
. * EXAMPLES
.
. * example from http://www.cdam.lse.ac.uk/Reports/Files/cdam-2001-09.pdf
.
. gamet, payoff(2, 2, 0, 1 \ 3, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(Provider) ls2(Customer) elids neps
----------------------------
| Customer
Provider | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (3; 0) (1; 1)
----------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Provider is High
No dominated strategy for Customer
Dominant strategy for Provider is Low
No dominant strategy for Customer
--------------------------
| Customer
Provider | Buy Not_bu
----------+---------------
Low | (3; 0) (1; 1)
--------------------------
Iteration 2
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Provider
Dominated strategy for Customer is Buy
Dominant strategy for Provider is Low
Dominant strategy for Customer is Not_buy
------------------
|Custome
| r
Provider | Not_bu
----------+-------
Low | (1; 1)
------------------
Iteration 3
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Provider
No dominated strategy for Customer
Dominant strategy for Provider is Low
Dominant strategy for Customer is Not_buy
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Low Not_buy (1; 1)
.
. gamet, payoff(2, 2, 0, 1 \ 1, 0 , 1, 1) player1(High Low) player2(Buy Not_bu
> y) ls1(Provider) ls2(Customer) elids neps
----------------------------
| Customer
Provider | Buy Not_buy
----------+-----------------
High | (2; 2) (0; 1)
Low | (1; 0) (1; 1)
----------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Provider
No dominated strategy for Customer
No dominant strategy for Provider
No dominant strategy for Customer
NASH EQUILIBRIUM IN PURE STRATEGIES
1. High Buy (2; 2)
2. Low Not_buy (1; 1)
.
. gamet, pay(0, 0, -10, 10 \ -1, 0, -6, -90) player1(Not_inspect Inspect) playe
> r2(Comply Cheat) ls1(I) ls2(II) nefms
----------------------------------
| II
I | Comply Cheat
------------+---------------------
Not_inspect | (0; 0) (-10; 10)
Inspect | (-1; 0) (-6; -90)
----------------------------------
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.90
q = 0.80
(0.90*[Not_inspect]+0.10*[Inspect], 0.80*[Comply]+0.20*[Cheat])
Expected equilibrium payoff for I
0.80*0+(1-0.80)*-10 = -2
0.80*-1+(1-0.80)*-6 = -2
Expected equilibrium payoff for II
0.90*0+(1-0.90)*0 = 0
0.90*10+(1-0.90)*-90 = 0
.
. gamet, payoff(-10,5, 8,-10\3, -1, 0,0) ls1(Iran) ls2(IAEA) player1(Make_nukes
> No_nukes) player2(Inspect Not_inspect) nefms
-------------------------------------
| IAEA
Iran | Inspect Not_inspect
-----------+-------------------------
Make_nukes | (-10; 5) (8; -10)
No_nukes | (3; -1) (0; 0)
-------------------------------------
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.06
q = 0.38
(0.06*[Make_nukes]+0.94*[No_nukes], 0.38*[Inspect]+0.62*[Not_inspect])
Expected equilibrium payoff for Iran
0.38*-10+(1-0.38)*8 = 1.1428571
0.38*3+(1-0.38)*0 = 1.1428571
Expected equilibrium payoff for IAEA
0.06*5+(1-0.06)*-1 = -.625
0.06*-10+(1-0.06)*0 = -.625
.
. gamet, pay(50, 50, 80, 20 \ 90, 10, 20 , 80) ls1(Serena) ls2(Venus) player1(
> DL CC) player2(DL CC) nefms
------------------------------
| Venus
Serena | DL CC
----------+-------------------
DL | (50; 50) (80; 20)
CC | (90; 10) (20; 80)
------------------------------
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.70
q = 0.60
(0.70*[DL]+0.30*[CC], 0.60*[DL]+0.40*[CC])
Expected equilibrium payoff for Serena
0.60*50+(1-0.60)*80 = 62
0.60*90+(1-0.60)*20 = 62
Expected equilibrium payoff for Venus
0.70*50+(1-0.70)*10 = 38
0.70*20+(1-0.70)*80 = 38
.
. gamet , pay(-1, -1, 3, 0 \ 0, 3, 0, 0) neps nefms elids
------------------------------
| S2
S1 | a1 b2
----------+-------------------
A1 | (-1; -1) (3; 0)
B2 | (0; 3) (0; 0)
------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. A1 b2 (3; 0)
2. B2 a1 (0; 3)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.75
q = 0.75
(0.75*[A1]+0.25*[B2], 0.75*[a1]+0.25*[b2])
Expected equilibrium payoff for S1
0.75*-1+(1-0.75)*3 = 0
0.75*0+(1-0.75)*0 = 0
Expected equilibrium payoff for S2
0.75*-1+(1-0.75)*3 = 0
0.75*0+(1-0.75)*0 = 0
.
. gamet , pay(-1, -1, 4, 0 \ 0, 3, 0, 0) neps nefms ls1(MD) ls2(DK) player1(E D
> ) player2(E D) elids
------------------------------
| DK
MD | E D
----------+-------------------
E | (-1; -1) (4; 0)
D | (0; 3) (0; 0)
------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for MD
No dominated strategy for DK
No dominant strategy for MD
No dominant strategy for DK
NASH EQUILIBRIUM IN PURE STRATEGIES
1. E D (4; 0)
2. D E (0; 3)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.75
q = 0.80
(0.75*[E]+0.25*[D], 0.80*[E]+0.20*[D])
Expected equilibrium payoff for MD
0.80*-1+(1-0.80)*4 = 0
0.80*0+(1-0.80)*0 = 0
Expected equilibrium payoff for DK
0.75*-1+(1-0.75)*3 = 0
0.75*0+(1-0.75)*0 = 0
.
. * examples from http://www.courses.fas.harvard.edu/~ec1052/lecture/lecture5.p
> df
.
. gamet, pay(1, 1, 0, 4 \ 0, 2, 2 , 1) neps nefms ls1(player1) ls2(player2) pla
> yer1(U D) player2(L R) elids
--------------------------
| player2
player1 | L R
----------+---------------
U | (1; 1) (0; 4)
D | (0; 2) (2; 1)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for player1
No dominated strategy for player2
No dominant strategy for player1
No dominant strategy for player2
NASH EQUILIBRIUM IN PURE STRATEGIES
None
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.25
q = 0.67
(0.25*[U]+0.75*[D], 0.67*[L]+0.33*[R])
Expected equilibrium payoff for player1
0.67*1+(1-0.67)*0 = .66666667
0.67*0+(1-0.67)*2 = .66666667
Expected equilibrium payoff for player2
0.25*1+(1-0.25)*2 = 1.75
0.25*4+(1-0.25)*1 = 1.75
.
. gamet , pay(1, 1, 0, 2,0,4 \0,2,5,0,1,6 \0,2,1,1,2,1) player1(U M D) player2(
> L C R) elids
----------------------------------
| S2
S1 | L C R
----------+-----------------------
U | (1; 1) (0; 2) (0; 4)
M | (0; 2) (5; 0) (1; 6)
D | (0; 2) (1; 1) (2; 1)
----------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
Dominated strategy for S2 is C
No dominant strategy for S1
No dominant strategy for S2
--------------------------
| S2
S1 | L R
----------+---------------
U | (1; 1) (0; 4)
M | (0; 2) (1; 6)
D | (0; 2) (2; 1)
--------------------------
Iteration 2
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for S1 is M
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
--------------------------
| S2
S1 | L R
----------+---------------
U | (1; 1) (0; 4)
D | (0; 2) (2; 1)
--------------------------
Iteration 3
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
.
. gamet , pay(1, 1, 0, 2,0,4 \0,2,5,0,1,6 \0,2,1,1,2,1) player1(U M D) player2(
> L C R) elids
----------------------------------
| S2
S1 | L C R
----------+-----------------------
U | (1; 1) (0; 2) (0; 4)
M | (0; 2) (5; 0) (1; 6)
D | (0; 2) (1; 1) (2; 1)
----------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
Dominated strategy for S2 is C
No dominant strategy for S1
No dominant strategy for S2
--------------------------
| S2
S1 | L R
----------+---------------
U | (1; 1) (0; 4)
M | (0; 2) (1; 6)
D | (0; 2) (2; 1)
--------------------------
Iteration 2
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for S1 is M
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
--------------------------
| S2
S1 | L R
----------+---------------
U | (1; 1) (0; 4)
D | (0; 2) (2; 1)
--------------------------
Iteration 3
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
.
. * examples from http://web.mit.edu/14.12/www/02F_lecture102.pdf
.
. gamet, pay(-1, -1, 1, -10\ -10, 1, 2, 2) player1(C D) player2(C D) elids neps
> nefms
------------------------------
| S2
S1 | C D
----------+-------------------
C | (-1; -1) (1; -10)
D | (-10; 1) (2; 2)
------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. C C (-1; -1)
2. D D (2; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.10
q = 0.10
(0.10*[C]+0.90*[D], 0.10*[C]+0.90*[D])
Expected equilibrium payoff for S1
0.10*-1+(1-0.10)*1 = .8
0.10*-10+(1-0.10)*2 = .8
Expected equilibrium payoff for S2
0.10*-1+(1-0.10)*1 = .8
0.10*-10+(1-0.10)*2 = .8
.
. * examples from http://web.mit.edu/14.12/www/02F_slides5_602.pdf (there is a
> range)
.
. * gamet, pay(2, 2, 4, 0 \0, 4, 5, 0) player1(Rabbit Stang) player2(Rabbit Sta
> ng) elids neps nefms
.
. * examples from http://www.virtualperfection.com/gametheory/3.1.Nash%20Equili
> brium.1.0.pdf
.
. gamet, payoff(9,9,0,8 \ 8,0,7,7) player1(U D) player2(l r) elids neps nefms
--------------------------
| S2
S1 | l r
----------+---------------
U | (9; 9) (0; 8)
D | (8; 0) (7; 7)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. U l (9; 9)
2. D r (7; 7)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.88
q = 0.88
(0.88*[U]+0.13*[D], 0.88*[l]+0.13*[r])
Expected equilibrium payoff for S1
0.88*9+(1-0.88)*0 = 7.875
0.88*8+(1-0.88)*7 = 7.875
Expected equilibrium payoff for S2
0.88*9+(1-0.88)*0 = 7.875
0.88*8+(1-0.88)*7 = 7.875
.
. gamet, payoff(2,1,0,0 \ 0,0,1,2) player1(U D) player2(l r) elids neps nefms
--------------------------
| S2
S1 | l r
----------+---------------
U | (2; 1) (0; 0)
D | (0; 0) (1; 2)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. U l (2; 1)
2. D r (1; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.67
q = 0.33
(0.67*[U]+0.33*[D], 0.33*[l]+0.67*[r])
Expected equilibrium payoff for S1
0.33*2+(1-0.33)*0 = .66666667
0.33*0+(1-0.33)*1 = .66666667
Expected equilibrium payoff for S2
0.67*1+(1-0.67)*0 = .66666667
0.67*0+(1-0.67)*2 = .66666667
.
. * examples from http://www.virtualperfection.com/gametheory/3.2.NashEq2x2Norm
> alFormGames.1.0.pdf
.
. gamet, payoff(1,-1,3,0 \ 4,2 ,0,-1) player1(U D) player2(l r) ls1(A) ls2(B) e
> lids neps nefms
----------------------------
| B
A | l r
----------+-----------------
U | (1; -1) (3; 0)
D | (4; 2) (0; -1)
----------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for A
No dominated strategy for B
No dominant strategy for A
No dominant strategy for B
NASH EQUILIBRIUM IN PURE STRATEGIES
1. U r (3; 0)
2. D l (4; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.75
q = 0.50
(0.75*[U]+0.25*[D], 0.50*[l]+0.50*[r])
Expected equilibrium payoff for A
0.50*1+(1-0.50)*3 = 2
0.50*4+(1-0.50)*0 = 2
Expected equilibrium payoff for B
0.75*-1+(1-0.75)*2 = -.25
0.75*0+(1-0.75)*-1 = -.25
.
. gamet, payoff(1,1.5,3,1 \ 4,2 ,3,3) player1(U D) player2(l r) ls1(A) ls2(B) e
> lids neps nefms
------------------------------
| B
A | l r
----------+-------------------
U | (1; 1.5) (3; 1)
D | (4; 2) (3; 3)
------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for A
No dominated strategy for B
No dominant strategy for A
No dominant strategy for B
NASH EQUILIBRIUM IN PURE STRATEGIES
1. D r (3; 3)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.67
q = 0.00
(0.67*[U]+0.33*[D], 0.00*[l]+1.00*[r])
Expected equilibrium payoff for A
0.00*1+(1-0.00)*3 = 3
0.00*4+(1-0.00)*3 = 3
Expected equilibrium payoff for B
0.67*1.5+(1-0.67)*2 = 1.6666667
0.67*1+(1-0.67)*3 = 1.6666667
.
. * examples from http://levine.sscnet.ucla.edu/econ201/game.pdf
.
. gamet, payoff(1,1,0,0 \ 0,0,1,1) player1(U D) player2(l r) ls1(A) ls2(B) elid
> s neps nefms
--------------------------
| B
A | l r
----------+---------------
U | (1; 1) (0; 0)
D | (0; 0) (1; 1)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for A
No dominated strategy for B
No dominant strategy for A
No dominant strategy for B
NASH EQUILIBRIUM IN PURE STRATEGIES
1. U l (1; 1)
2. D r (1; 1)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.50
q = 0.50
(0.50*[U]+0.50*[D], 0.50*[l]+0.50*[r])
Expected equilibrium payoff for A
0.50*1+(1-0.50)*0 = .5
0.50*0+(1-0.50)*1 = .5
Expected equilibrium payoff for B
0.50*1+(1-0.50)*0 = .5
0.50*0+(1-0.50)*1 = .5
.
. gamet, payoff(2,2,-10,0 \ 0,-10,1,1) player1(U D) player2(l r) ls1(A) ls2(B)
> elids neps nefms
------------------------------
| B
A | l r
----------+-------------------
U | (2; 2) (-10; 0)
D | (0; -10) (1; 1)
------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for A
No dominated strategy for B
No dominant strategy for A
No dominant strategy for B
NASH EQUILIBRIUM IN PURE STRATEGIES
1. U l (2; 2)
2. D r (1; 1)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.85
q = 0.85
(0.85*[U]+0.15*[D], 0.85*[l]+0.15*[r])
Expected equilibrium payoff for A
0.85*2+(1-0.85)*-10 = .15384615
0.85*0+(1-0.85)*1 = .15384615
Expected equilibrium payoff for B
0.85*2+(1-0.85)*-10 = .15384615
0.85*0+(1-0.85)*1 = .15384615
.
. gamet, payoff(6,6,2,7 \ 7,2,0,0) player1(U D) player2(l r) ls1(A) ls2(B) elid
> s neps nefms
--------------------------
| B
A | l r
----------+---------------
U | (6; 6) (2; 7)
D | (7; 2) (0; 0)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for A
No dominated strategy for B
No dominant strategy for A
No dominant strategy for B
NASH EQUILIBRIUM IN PURE STRATEGIES
1. U r (2; 7)
2. D l (7; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.67
q = 0.67
(0.67*[U]+0.33*[D], 0.67*[l]+0.33*[r])
Expected equilibrium payoff for A
0.67*6+(1-0.67)*2 = 4.6666667
0.67*7+(1-0.67)*0 = 4.6666667
Expected equilibrium payoff for B
0.67*6+(1-0.67)*2 = 4.6666667
0.67*7+(1-0.67)*0 = 4.6666667
.
. * examples from http://www.polisci.ucsd.edu/~bslantch/courses/gt/problem-sets
> /w0403s.pdf
.
. gamet, payoff(2,2,1,3\ 3,1,0,0) ls1(Player1) ls2(Player2) player1(D H) player
> 2(D H) elids neps nefms
--------------------------
| Player2
Player1 | D H
----------+---------------
D | (2; 2) (1; 3)
H | (3; 1) (0; 0)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. D H (1; 3)
2. H D (3; 1)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.50
q = 0.50
(0.50*[D]+0.50*[H], 0.50*[D]+0.50*[H])
Expected equilibrium payoff for Player1
0.50*2+(1-0.50)*1 = 1.5
0.50*3+(1-0.50)*0 = 1.5
Expected equilibrium payoff for Player2
0.50*2+(1-0.50)*1 = 1.5
0.50*3+(1-0.50)*0 = 1.5
.
. gamet, payoff(1,1,0,0\ 0,0,1,1) ls1(Player1) ls2(Player2) player1(Bridge Barn
> ) player2(Bridge Barn) elids neps nefms
--------------------------
| Player2
Player1 | Bridge Barn
----------+---------------
Bridge | (1; 1) (0; 0)
Barn | (0; 0) (1; 1)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Bridge Bridge (1; 1)
2. Barn Barn (1; 1)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.50
q = 0.50
(0.50*[Bridge]+0.50*[Barn], 0.50*[Bridge]+0.50*[Barn])
Expected equilibrium payoff for Player1
0.50*1+(1-0.50)*0 = .5
0.50*0+(1-0.50)*1 = .5
Expected equilibrium payoff for Player2
0.50*1+(1-0.50)*0 = .5
0.50*0+(1-0.50)*1 = .5
.
. gamet, payoff(1,1,0,0\ 0,0,2,2) ls1(Player1) ls2(Player2) player1(Bridge Barn
> ) player2(Bridge Barn) elids neps nefms
--------------------------
| Player2
Player1 | Bridge Barn
----------+---------------
Bridge | (1; 1) (0; 0)
Barn | (0; 0) (2; 2)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Bridge Bridge (1; 1)
2. Barn Barn (2; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.67
q = 0.67
(0.67*[Bridge]+0.33*[Barn], 0.67*[Bridge]+0.33*[Barn])
Expected equilibrium payoff for Player1
0.67*1+(1-0.67)*0 = .66666667
0.67*0+(1-0.67)*2 = .66666667
Expected equilibrium payoff for Player2
0.67*1+(1-0.67)*0 = .66666667
0.67*0+(1-0.67)*2 = .66666667
.
. gamet, payoff(0,1,1,0\ 1,0,0,1) ls1(Player1) ls2(Player2) player1(A B) player
> 2(A B) elids neps nefms
--------------------------
| Player2
Player1 | A B
----------+---------------
A | (0; 1) (1; 0)
B | (1; 0) (0; 1)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
None
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.50
q = 0.50
(0.50*[A]+0.50*[B], 0.50*[A]+0.50*[B])
Expected equilibrium payoff for Player1
0.50*0+(1-0.50)*1 = .5
0.50*1+(1-0.50)*0 = .5
Expected equilibrium payoff for Player2
0.50*1+(1-0.50)*0 = .5
0.50*0+(1-0.50)*1 = .5
.
. gamet, payoff(1,-1,3,0\ 4,2,0,-1) ls1(Player1) ls2(Player2) player1(D H) play
> er2(D H) elids neps nefms
----------------------------
| Player2
Player1 | D H
----------+-----------------
D | (1; -1) (3; 0)
H | (4; 2) (0; -1)
----------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. D H (3; 0)
2. H D (4; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.75
q = 0.50
(0.75*[D]+0.25*[H], 0.50*[D]+0.50*[H])
Expected equilibrium payoff for Player1
0.50*1+(1-0.50)*3 = 2
0.50*4+(1-0.50)*0 = 2
Expected equilibrium payoff for Player2
0.75*-1+(1-0.75)*2 = -.25
0.75*0+(1-0.75)*-1 = -.25
.
. gamet, payoff(0,0,1,0\ 0,1,3,3) ls1(Player1) ls2(Player2) player1(D H) player
> 2(D H) elids neps nefms
--------------------------
| Player2
Player1 | D H
----------+---------------
D | (0; 0) (1; 0)
H | (0; 1) (3; 3)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
1. D D (0; 0)
2. H H (3; 3)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 1.00
q = 1.00
(1.00*[D]+0.00*[H], 1.00*[D]+0.00*[H])
Expected equilibrium payoff for Player1
1.00*0+(1-1.00)*1 = 0
1.00*0+(1-1.00)*3 = 0
Expected equilibrium payoff for Player2
1.00*0+(1-1.00)*1 = 0
1.00*0+(1-1.00)*3 = 0
.
. * examples from http://www.andrew.cmu.edu/user/xinming/gametheory/
.
. * gamet, pay(-1,-1, -9,0 \ 0, -9, -6,-6) ls1(Prisoner1) ls2(Prisoner2) player
> 1(mum confess) player2(mum confess) elids neps nefms
.
. gamet, pay(-1,1,1,-1\1,-1,-1,1) player1(Head Tail) player2(Head Tail) elids n
> eps nefms
----------------------------
| S2
S1 | Head Tail
----------+-----------------
Head | (-1; 1) (1; -1)
Tail | (1; -1) (-1; 1)
----------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for S1
No dominated strategy for S2
No dominant strategy for S1
No dominant strategy for S2
NASH EQUILIBRIUM IN PURE STRATEGIES
None
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.50
q = 0.50
(0.50*[Head]+0.50*[Tail], 0.50*[Head]+0.50*[Tail])
Expected equilibrium payoff for S1
0.50*-1+(1-0.50)*1 = 0
0.50*1+(1-0.50)*-1 = 0
Expected equilibrium payoff for S2
0.50*1+(1-0.50)*-1 = 0
0.50*-1+(1-0.50)*1 = 0
.
. gamet, pay(2, 1, 0, 0 \ 0,0, 1, 2) ls1(Chris) ls2(Pat) player1(Opera Prize_Fi
> ght) player2(Opera Prize_Fight) elids neps nefms
--------------------------------------
| Pat
Chris | Opera Prize_Fight
------------+-------------------------
Opera | (2; 1) (0; 0)
Prize_Fight | (0; 0) (1; 2)
--------------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Chris
No dominated strategy for Pat
No dominant strategy for Chris
No dominant strategy for Pat
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Opera Opera (2; 1)
2. Prize_Fight Prize_Fight (1; 2)
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.67
q = 0.33
(0.67*[Opera]+0.33*[Prize_Fight], 0.33*[Opera]+0.67*[Prize_Fight])
Expected equilibrium payoff for Chris
0.33*2+(1-0.33)*0 = .66666667
0.33*0+(1-0.33)*1 = .66666667
Expected equilibrium payoff for Pat
0.67*1+(1-0.67)*0 = .66666667
0.67*0+(1-0.67)*2 = .66666667
.
. gamet, pay(50, 90, 50, 100 \0, -10, 100, -100) ls1(Employee) ls2(Manager) pla
> yer1(Work Shirk) player2(Monitor Not_monitor) elids neps nefms
------------------------------------
| Manager
Employee | Monitor Not_monitor
----------+-------------------------
Work | (50; 90) (50; 100)
Shirk | (0; -10) (100; -100)
------------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Employee
No dominated strategy for Manager
No dominant strategy for Employee
No dominant strategy for Manager
NASH EQUILIBRIUM IN PURE STRATEGIES
None
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.90
q = 0.50
(0.90*[Work]+0.10*[Shirk], 0.50*[Monitor]+0.50*[Not_monitor])
Expected equilibrium payoff for Employee
0.50*50+(1-0.50)*50 = 50
0.50*0+(1-0.50)*100 = 50
Expected equilibrium payoff for Manager
0.90*90+(1-0.90)*-10 = 80
0.90*100+(1-0.90)*-100 = 80
.
. gamet, pay(6,4,2,6 \3,3,6,1) ls1(Player1) ls2(Player2) player1(T B) player2(L
> R) elids neps nefms
--------------------------
| Player2
Player1 | L R
----------+---------------
T | (6; 4) (2; 6)
B | (3; 3) (6; 1)
--------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player1
No dominated strategy for Player2
No dominant strategy for Player1
No dominant strategy for Player2
NASH EQUILIBRIUM IN PURE STRATEGIES
None
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.50
q = 0.57
(0.50*[T]+0.50*[B], 0.57*[L]+0.43*[R])
Expected equilibrium payoff for Player1
0.57*6+(1-0.57)*2 = 4.2857143
0.57*3+(1-0.57)*6 = 4.2857143
Expected equilibrium payoff for Player2
0.50*4+(1-0.50)*3 = 3.5
0.50*6+(1-0.50)*1 = 3.5
.
. * Prisoner's dilemma
.
. gamet , payoff(-5, -5, 0 , -6 \ -6, 0 , -1, -1) player1(Confess Not_confess)
> player2(Confess Not_confess) domist neps
--------------------------------------
| S2
S1 | Confess Not_confess
------------+-------------------------
Confess | (-5; -5) (0; -6)
Not_confess | (-6; 0) (-1; -1)
--------------------------------------
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for S1 is Not_confess
Dominated strategy for S2 is Not_confess
Dominant strategy for S1 is Confess
Dominant strategy for S2 is Confess
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Confess Confess (-5; -5)
.
. gamet, payoff(3, 3, 0, 5 \ 5, 0 , 1, 1) player1(C D) player2(C D) ls1(Provid
> er) ls2(Customer) domist neps
--------------------------
| Customer
Provider | C D
----------+---------------
C | (3; 3) (0; 5)
D | (5; 0) (1; 1)
--------------------------
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for Provider is C
Dominated strategy for Customer is C
Dominant strategy for Provider is D
Dominant strategy for Customer is D
NASH EQUILIBRIUM IN PURE STRATEGIES
1. D D (1; 1)
.
. gamet, payoff(-3, -3, 0, -5 \ -5, 0 , -1, -1) player1(C D) player2(C D) dom
> ist neps
------------------------------
| S2
S1 | C D
----------+-------------------
C | (-3; -3) (0; -5)
D | (-5; 0) (-1; -1)
------------------------------
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for S1 is D
Dominated strategy for S2 is D
Dominant strategy for S1 is C
Dominant strategy for S2 is C
NASH EQUILIBRIUM IN PURE STRATEGIES
1. C C (-3; -3)
.
. gamet, payoff(-10,5, 8,-10\3, -1, 0,0) ls1(Player_1) ls2(Player_2) player1(Up
> Down) player2(Left Right) elids neps nefms
------------------------------
| Player_2
Player_1 | Left Right
----------+-------------------
Up | (-10; 5) (8; -10)
Down | (3; -1) (0; 0)
------------------------------
Iteration 1
DOMINATED AND DOMINANT STRATEGIES
No dominated strategy for Player_1
No dominated strategy for Player_2
No dominant strategy for Player_1
No dominant strategy for Player_2
NASH EQUILIBRIUM IN PURE STRATEGIES
None
NASH EQUILIBRIUM IN FULLY MIXED STRATEGIES
p = 0.06
q = 0.38
(0.06*[Up]+0.94*[Down], 0.38*[Left]+0.62*[Right])
Expected equilibrium payoff for Player_1
0.38*-10+(1-0.38)*8 = 1.1428571
0.38*3+(1-0.38)*0 = 1.1428571
Expected equilibrium payoff for Player_2
0.06*5+(1-0.06)*-1 = -.625
0.06*-10+(1-0.06)*0 = -.625
.
. gamet , payoff(5, 5, 0 , 6 \ 6, 0 , 1, 1) player1(Confess Not_confess) player
> 2(Confess Not_confess) domist neps
--------------------------------------
| S2
S1 | Confess Not_confess
------------+-------------------------
Confess | (5; 5) (0; 6)
Not_confess | (6; 0) (1; 1)
--------------------------------------
DOMINATED AND DOMINANT STRATEGIES
Dominated strategy for S1 is Confess
Dominated strategy for S2 is Confess
Dominant strategy for S1 is Not_confess
Dominant strategy for S2 is Not_confess
NASH EQUILIBRIUM IN PURE STRATEGIES
1. Not_confess Not_confess (1; 1)