4
1.
1.
(a)
(b)
(c)
(d)
(e)
2.
(a)
(b)
(c)3








(N, v)
min
∑
i∈N
xi
∑
i∈S
xi ≥ v(S), ∀S ⊊ N
z* z* ≤ v(N)








(N, v)
min
∑
i∈N
xi
∑
i∈S
xi ≥ v(S), ∀S ⊊ N
z* z* ≤ v(N)
z*, w*
z* = w*








max
∑
S⊊N
v(S)yS
s . t .
∑
S:i∈S⊊N
yS = 1, ∀i ∈ N
yS ≥ 0, ∀S ⊊ N








(N, v)
max
∑
S⊊N
v(S)yS
s . t .
∑
S:i∈S⊊N
yS = 1, ∀i ∈ N
yS ≥ 0, ∀S ⊊ N
w* w* ≤ v(N)












(N, v)
∑
S:i∈S⊊N
yS = 1, ∀i ∈ N
2n
− 2 y = (yS : S ⊊ N)
∑
S⊊N
v(S)yS ≤ v(N)




w* w* ≤ v(N)
y
















∑
S:i∈S⊊N
yS = 1, ∀i ∈ N
N = {1,⋯, n} C = {S1, ⋯, Sm}
γ1, ⋯, γm
∑
j:i∈Sj
γj = 1, ∀i ∈ N
γ = (γ1, ⋯, γm) C






y{1} + y{1,2} + y{1,3} = 1
y{2} + y{1,2} + y{2,3} = 1
y{3} + y{1,3} + y{2,3} = 1
S = ∅ S = N




















(N, v) N = {1,⋯, n} C = {S1, ⋯, Sm}
γ = (γ1, ⋯, γm)
∑
S⊊N
γSv(Sj) ≤ v(N)




















(N, v) N = {1,⋯, n} C = {S1, ⋯, Sm}
γ = (γ1, ⋯, γm)
∑
S⊊N
γSv(Sj) ≤ v(N)








(N, v)
∑
S:i∈S⊊N
yS = 1, ∀i ∈ N
2n
− 2 y = (yS : S ⊊ N)
∑
S⊊N
v(S)yS ≤ v(N)




















(N, v) N = {1,⋯, n} C = {S1, ⋯, Sm}
γ = (γ1, ⋯, γm)
∑
S⊊N
γSv(Sj) ≤ v(N)








(N, v)
∑
S:i∈S⊊N
yS = 1, ∀i ∈ N
2n
− 2 y = (yS : S ⊊ N)
∑
S⊊N
v(S)yS ≤ v(N)

(N, v)
3
















(N, v)
{{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1)
i = 1
∑
j:1∈Sj
γj = γ1 = 1
i = 2, 3
{{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = (
1
2
,
1
2
,
1
2
)
i = 1
∑
j:1∈Sj
γj = γ12 + γ13 =
1
2
+
1
2
= 1
i = 2, 3
{{1}, {2}, {3}, {1,2}, {1,3}, {2,3}}
γ = (γ1, γ2, γ3, γ12, γ13, γ23) = (γ*, γ*, γ*,
1 − γ*
2
,
1 − γ*
2
,
1 − γ*
2
) 0 < γ* < 1








N = {1,⋯, n} C = {S1, ⋯, Sm}
γ1, ⋯, γm
∑
j:i∈Sj
γj = 1, ∀i ∈ N
γ = (γ1, ⋯, γm) C














{{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1)
{{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = (
1
2
,
1
2
,
1
2
)
{{1}, {2}, {3}, {1,2}, {1,3}, {2,3}}
γ = (γ1, γ2, γ3, γ12, γ13, γ23) = (γ*, γ*, γ*,
1 − γ*
2
,
1 − γ*
2
,
1 − γ*
2
) 0 < γ* < 1
∑
S⊊N
v(S)γS ≤ v(N)
v({1})γ1 + v({2})γ2 + v({3})γ3 ≤ v(N) ⇔ v({1}) + v({2}) + v({3}) ≤ v(N)
v({1,2})γ12 + v({1,3})γ1,3 + v({2,3})γ23 ≤ v(N) ⇔
1
2
v({1,2}) +
1
2
v({1,3}) +
1
2
v({2,3}) ≤ v(N)
γ* 0 < γ* < 1 γ* (1 − γ*)
γ*v({1}) + γ*v({2}) + γ*v({3}) +
(1 − γ*)
2
v({1,2}) +
(1 − γ*)
2
v({1,3}) +
(1 − γ*)
2
v({2,3}) ≤ v(N)










(N, v)
N = {1,⋯, n} C = {S1, ⋯, Sm}
γ = (γ1, ⋯, γm)
∑
S⊊N
γSv(Sj) ≤ v(N)






















Γ Γ′ ⊂ Γ Γ′ Γ
{{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1)
{{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = (
1
2
,
1
2
,
1
2
)
{{1}, {2}, {3}, {1,2}, {1,3}, {2,3}}
γ = (γ1, γ2, γ3, γ12, γ13, γ23) = (γ1, γ1, γ1,
1 − γ1
2
,
1 − γ1
2
,
1 − γ1
2
) 0 < γ1 < 1
{{1}, {2}, {3}} ⊂ {{1}, {2}, {3}, {1,2}, {1,3}, {2,3}} {{1}, {2}, {3}}




























Γ Γ′ ⊂ Γ Γ′ Γ
{{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1)
{{1}, {2, 3}} γ = (γ1, γ23) = (1,1)
{{2}, {1, 3}} γ = (γ2, γ13) = (1,1)
{{3}, {1, 2}} γ = (γ3, γ12) = (1,1)
{{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = (
1
2
,
1
2
,
1
2
)


























Γ Γ′ ⊂ Γ Γ′ Γ
{{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1)
{{1}, {2, 3}} γ = (γ1, γ23) = (1,1)
{{2}, {1, 3}} γ = (γ2, γ13) = (1,1)
{{3}, {1, 2}} γ = (γ3, γ12) = (1,1)
{{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = (
1
2
,
1
2
,
1
2
)

(N, v) N = {1,⋯, n} C = {S1, ⋯, Sm}
γ = (γ1, ⋯, γm)
∑
S⊊N
γSv(Sj) ≤ v(N)






















(N, v)
v({1,2}) + v({2,3}) + v({1,3}) ≤ 2v({1,2,3})
{{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1)
γ1v({1}) + γ2v({2}) + γ3v({3}) = v({1}) + v({2}) + v({3})
≤ v({1,2}) + v({3}) ≤ v({1,2,3}))
{{1}, {2, 3}} γ = (γ1, γ23) = (1,1)
γ1v({1}) + γ23v({2,3}) = v({1}) + v({2,3}) ≤ v({1,2,3})
{{2}, {1, 3}} γ = (γ2, γ13) = (1,1)
{{3}, {1, 2}} γ = (γ3, γ12) = (1,1)
{{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = (
1
2
,
1
2
,
1
2
)
γ12v({1,2}) + γ2,3v({2,3}) + γ1,3v({1,3}) =
1
2
v({1,2}) +
1
2
v({2,3}) +
1
2
v({1,3}) v({1,2,3})




(N, v)
N = {1,⋯, n} C = {S1, ⋯, Sm}
γ = (γ1, ⋯, γm)
∑
S⊊N
γSv(Sj) ≤ v(N)
See you next time



ゲーム理論NEXT コア第4回(最終回) -平衡ゲームとコア-

  • 1.
  • 2.
  • 3.
  • 5.
  • 6.
    
 
 
 
 (N, v) min ∑ i∈N xi ∑ i∈S xi ≥v(S), ∀S ⊊ N z* z* ≤ v(N) z*, w* z* = w* 
 
 
 
 max ∑ S⊊N v(S)yS s . t . ∑ S:i∈S⊊N yS = 1, ∀i ∈ N yS ≥ 0, ∀S ⊊ N
  • 7.
    
 
 
 
 (N, v) max ∑ S⊊N v(S)yS s .t . ∑ S:i∈S⊊N yS = 1, ∀i ∈ N yS ≥ 0, ∀S ⊊ N w* w* ≤ v(N)
  • 8.
    
 
 
 
 
 
 (N, v) ∑ S:i∈S⊊N yS =1, ∀i ∈ N 2n − 2 y = (yS : S ⊊ N) ∑ S⊊N v(S)yS ≤ v(N) 
 
 w* w* ≤ v(N) y
  • 9.
    
 
 
 
 
 
 
 
 ∑ S:i∈S⊊N yS = 1,∀i ∈ N N = {1,⋯, n} C = {S1, ⋯, Sm} γ1, ⋯, γm ∑ j:i∈Sj γj = 1, ∀i ∈ N γ = (γ1, ⋯, γm) C 
 
 
 y{1} + y{1,2} + y{1,3} = 1 y{2} + y{1,2} + y{2,3} = 1 y{3} + y{1,3} + y{2,3} = 1 S = ∅ S = N
  • 10.
    
 
 
 
 
 
 
 
 
 
 (N, v) N= {1,⋯, n} C = {S1, ⋯, Sm} γ = (γ1, ⋯, γm) ∑ S⊊N γSv(Sj) ≤ v(N)
  • 11.
    
 
 
 
 
 
 
 
 
 
 (N, v) N= {1,⋯, n} C = {S1, ⋯, Sm} γ = (γ1, ⋯, γm) ∑ S⊊N γSv(Sj) ≤ v(N) 
 
 
 
 (N, v) ∑ S:i∈S⊊N yS = 1, ∀i ∈ N 2n − 2 y = (yS : S ⊊ N) ∑ S⊊N v(S)yS ≤ v(N)
  • 12.
    
 
 
 
 
 
 
 
 
 
 (N, v) N= {1,⋯, n} C = {S1, ⋯, Sm} γ = (γ1, ⋯, γm) ∑ S⊊N γSv(Sj) ≤ v(N) 
 
 
 
 (N, v) ∑ S:i∈S⊊N yS = 1, ∀i ∈ N 2n − 2 y = (yS : S ⊊ N) ∑ S⊊N v(S)yS ≤ v(N) 
(N, v)
  • 13.
  • 14.
    
 
 
 
 
 
 
 
 (N, v) {{1}, {2},{3}} γ = (γ1, γ2, γ3) = (1,1,1) i = 1 ∑ j:1∈Sj γj = γ1 = 1 i = 2, 3 {{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = ( 1 2 , 1 2 , 1 2 ) i = 1 ∑ j:1∈Sj γj = γ12 + γ13 = 1 2 + 1 2 = 1 i = 2, 3 {{1}, {2}, {3}, {1,2}, {1,3}, {2,3}} γ = (γ1, γ2, γ3, γ12, γ13, γ23) = (γ*, γ*, γ*, 1 − γ* 2 , 1 − γ* 2 , 1 − γ* 2 ) 0 < γ* < 1 
 
 
 
 N = {1,⋯, n} C = {S1, ⋯, Sm} γ1, ⋯, γm ∑ j:i∈Sj γj = 1, ∀i ∈ N γ = (γ1, ⋯, γm) C
  • 15.
    
 
 
 
 
 
 
 {{1}, {2}, {3}}γ = (γ1, γ2, γ3) = (1,1,1) {{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = ( 1 2 , 1 2 , 1 2 ) {{1}, {2}, {3}, {1,2}, {1,3}, {2,3}} γ = (γ1, γ2, γ3, γ12, γ13, γ23) = (γ*, γ*, γ*, 1 − γ* 2 , 1 − γ* 2 , 1 − γ* 2 ) 0 < γ* < 1 ∑ S⊊N v(S)γS ≤ v(N) v({1})γ1 + v({2})γ2 + v({3})γ3 ≤ v(N) ⇔ v({1}) + v({2}) + v({3}) ≤ v(N) v({1,2})γ12 + v({1,3})γ1,3 + v({2,3})γ23 ≤ v(N) ⇔ 1 2 v({1,2}) + 1 2 v({1,3}) + 1 2 v({2,3}) ≤ v(N) γ* 0 < γ* < 1 γ* (1 − γ*) γ*v({1}) + γ*v({2}) + γ*v({3}) + (1 − γ*) 2 v({1,2}) + (1 − γ*) 2 v({1,3}) + (1 − γ*) 2 v({2,3}) ≤ v(N) 
 
 
 
 
 (N, v) N = {1,⋯, n} C = {S1, ⋯, Sm} γ = (γ1, ⋯, γm) ∑ S⊊N γSv(Sj) ≤ v(N)
  • 16.
    
 
 
 
 
 
 
 
 
 
 
 Γ Γ′ ⊂Γ Γ′ Γ {{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1) {{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = ( 1 2 , 1 2 , 1 2 ) {{1}, {2}, {3}, {1,2}, {1,3}, {2,3}} γ = (γ1, γ2, γ3, γ12, γ13, γ23) = (γ1, γ1, γ1, 1 − γ1 2 , 1 − γ1 2 , 1 − γ1 2 ) 0 < γ1 < 1 {{1}, {2}, {3}} ⊂ {{1}, {2}, {3}, {1,2}, {1,3}, {2,3}} {{1}, {2}, {3}}
  • 17.
    
 
 
 
 
 
 
 
 
 
 
 
 
 
 Γ Γ′ ⊂Γ Γ′ Γ {{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1) {{1}, {2, 3}} γ = (γ1, γ23) = (1,1) {{2}, {1, 3}} γ = (γ2, γ13) = (1,1) {{3}, {1, 2}} γ = (γ3, γ12) = (1,1) {{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = ( 1 2 , 1 2 , 1 2 )
  • 18.
    
 
 
 
 
 
 
 
 
 
 
 
 
 Γ Γ′ ⊂Γ Γ′ Γ {{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1) {{1}, {2, 3}} γ = (γ1, γ23) = (1,1) {{2}, {1, 3}} γ = (γ2, γ13) = (1,1) {{3}, {1, 2}} γ = (γ3, γ12) = (1,1) {{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = ( 1 2 , 1 2 , 1 2 ) 
(N, v) N = {1,⋯, n} C = {S1, ⋯, Sm} γ = (γ1, ⋯, γm) ∑ S⊊N γSv(Sj) ≤ v(N)
  • 19.
    
 
 
 
 
 
 
 
 
 
 
 (N, v) v({1,2}) +v({2,3}) + v({1,3}) ≤ 2v({1,2,3}) {{1}, {2}, {3}} γ = (γ1, γ2, γ3) = (1,1,1) γ1v({1}) + γ2v({2}) + γ3v({3}) = v({1}) + v({2}) + v({3}) ≤ v({1,2}) + v({3}) ≤ v({1,2,3})) {{1}, {2, 3}} γ = (γ1, γ23) = (1,1) γ1v({1}) + γ23v({2,3}) = v({1}) + v({2,3}) ≤ v({1,2,3}) {{2}, {1, 3}} γ = (γ2, γ13) = (1,1) {{3}, {1, 2}} γ = (γ3, γ12) = (1,1) {{1,2}, {1,3}, {2,3}} γ = (γ12, γ13, γ23) = ( 1 2 , 1 2 , 1 2 ) γ12v({1,2}) + γ2,3v({2,3}) + γ1,3v({1,3}) = 1 2 v({1,2}) + 1 2 v({2,3}) + 1 2 v({1,3}) v({1,2,3}) 
 
 (N, v) N = {1,⋯, n} C = {S1, ⋯, Sm} γ = (γ1, ⋯, γm) ∑ S⊊N γSv(Sj) ≤ v(N)
  • 21.
    See you nexttime