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GAME THEORY Mathematical models of strategic interactions. COMPETITIVE GAMES. COOPERATIVE GAMES. 39. I. S. D. II. II. S. D. S. D. (0 , 1). (0 , 0). (1 , 0). (-1 , -1). Forms. normal extensive characteristic. 38. 37. Nobel prizes in Economics. PERFECT EQUILIBRIUM.
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GAME THEORY Mathematical models of strategic interactions COMPETITIVE GAMES COOPERATIVE GAMES 39
I S D II II S D S D (0 , 1) (0 , 0) (1 , 0) (-1 , -1) Forms • normal • extensive • characteristic 38
Nobel prizes in Economics PERFECT EQUILIBRIUM COOPERATION & CONFLICT MECHANISM DESIGN MARKET DESIGN & STABLE ALLOCATIONS 36
WAR Gulf,… ECONOMICS Oligopolies,… MARKETING Coca-Cola,… FINANCE Firms’ Control,… POLITICS Electoral Systems,… CLUB GAMES Bridge, Poker, Chess,… SPORTS Attack-Defence Strategies,… SOCIOLOGY Migrations,… ENGINEERING Safety in mechanical and civil en.,… MEDICINE Neurons,… PSYCHOLOGY Prisoner’s dilemma,… BIOLOGY Evolution,… ENVIRONMENT Pollution,… … LOGIC – PHILOSOPHY – RELIGION … 35
Marketing Game BG BS STRATEGIES OF B Market Market 2 , 0 1 , 1 0 , 2 S T R A T E G I E S OF A FIRM A 4 units of capital FIRM B 2 units of capital The winnings are referred to A 34
Marketing Game - 2 - B A 33
MAX MIN of B Marketing Game - 3 - Minmax Solution B A MAX MIN of A 32
31 Courtesy of Silver/MCK
30 Courtesy of Silver/MCK
29 Courtesy of Silver/MCK
Saddle Points 28 Courtesy of Silver/MCK
MAX MIN of A MAX MIN of B Saddle Points B A 27
- 5 Constant sum games 10-sum game zero-sum game 24
Terrorist’s Dilemma Min A C NC -5 -10 23
Terrorist’s Dilemma C NC C NC Min B -5 -10 22
Terrorist’s Dilemma C NC MaxMin A C NC Max Min of B 21
Terrorist’s Dilemma NASH COOPERATIVE SOLUTION COMPETITIVE SOLUTION 20
Min USA -200 -∞ Min URSS -200 -∞ USA vs URSS winning 1200 – expense arm. 200 = earning 1000 A D A (-200, -200) (1000, -∞) D (-∞, 1000) (0, 0) 19
(-10, 0) (0, -10) (-∞, -∞) Overtaking Game (-∞, -∞) Competitive solution 18
Overtaking Game - 2 - Cooperative solution (-10, 0) (0, -10) (-∞, -∞) 17
(1, 2) (2, 1) (-1, -1) Mixed Maxmin The battle of the Sexes Pure Maxmin: (-1, -1) Mixed Maxmin: (1/5, 1/5) (x1 = 2/5, x2 = 3/5, y1 = 3/5, y2 = 2/5) (1/5, 1/5) Pure Maxmin 16
Christian IV of Denmark XVI – XVII century The captain has to declare the value of the cargo. The king can decide: - to apply taxes - to buy the cargo at the declared price 15
Christian IV of Denmark XVI – XVII century V = value of the cargo (=100) D = value declared by the captain (80, 90, …) T = Tax [0, 1] (=10%) K I N G 14
The revenue Inspector R = Real amount of the tax (=100) E = Evasion C = Cost of the examination (=20) P = Penality (=2) 13
Three players S T R A T E G I E S O F C , -9 3, 12 STRATEGIES OF B STRATEGIES OF A 12
Pollution Current situation: (-100, -100) Cost of the project: -150 9
Pollution - 2 - ( -150,0 (-75, -75) (-100, -100) (0,-150) 8
I S D II II S D S D I I I I S D S D S D S D II II II II II II II II S D S D S D S D S D S D S D S D (3,-1) (2,2) (3,4) (1,3) (0,-1) (-2,0) (5,-2) (3,8) (4,2) (1,2) (0,4) (1,-2) (0,1) (5,5) (2,-8) (7,-3) Games in Extensive Form 7
8 2 5 3 6 1 4 7 3 ->4 3 -> 5 6 ->5 …… 4->6 1 ->3 2 ->3 8->6 7->6 Winner: Winner: 6
8 2 5 3 6 1 4 7 3 ->4 3 -> 5 6 ->5 4->6 1 ->3 2 ->3 …… …… 5->1 Winner: 5
3 4 3 5 6 5 6 4 5 6 1 3 2 3 1 3 4 6 2 3 7 5 5 1 8 6 winner 8 4 8 6 76 4 2 76 winner winner winner 1 3 2 3 5 7 4 8 winner winner 5 1 4 2 winner winner winner 4
Games in characteristic function form ECONOMICS Oligopolies,.. FINANCE Firms’ Control,… POLITICS Electoral Systems,… SOCIOLOGY Migrations,… MEDICINE Neurons,… ENVIRONMENT Kyoto,… 3
He and she • 2 sons • Pentagon • Pens • Formulae • Blonde • The Speech • I need… 2
POESIE ed. Campanotto - Pasian di Prato (UD) 41
MY WARMEST THANKS TO... gianfranco.gambarelli @unibg.it 1