5. ݁ୗੑφογϡߧۉͷఆٛ
݁ୗੑͱ੍ࣗڧݾత
Λҙʹ༩͑ΒΕͨઓུͷͱ͢Δ
֤ ʹ͍ͭͯ ͕෦ήʔϜ ʹ͓͍ͯ݁ୗੑΛͭͱ
Ͱ͋Δ͜ͱΛ͍͏
ʮ֤ఏܞ ͨͩ͠
ʹର͠
͕෦ήʔϜ ʹ͓͍ͯ݁ୗੑΛͭʯ
ɹɹͱ͍͏͜ͱ͕ఆٛ͞Εͨͱ͢Δ͜ͷͱ͖֤ఏܞ ͨͩ͠
ʹ͍ͭͯ
B
͕෦ήʔϜ ʹ੍͓͍ͯࣗڧݾతͰ͋Δͱ
ͷͯ͢ͷਅ෦ू߹ ʹର͠
ʹ͓͍ͯ݁ୗੑΛͭ͜ͱΛ͍͏
C
͕෦ήʔϜ ʹ͓͍ͯ݁ୗੑͰ͋Δͱ
ʹ੍͓͍ͯࣗڧݾతͰ͋ͬͯ
͔͠ Λຬͨ͢Α͏ͳ
ʹ͓͚Δ੍ࣗڧݾతͳ ͕ଘࡏ͠ͳ͍͜ͱΛ͍͏
x ∈ X
i ∈ N xi G|xN{i}
∀yi ∈ Xi, ui(x) ≥ ui(yi, xN{i})
S ⊆ N 1 ≤ |S| m xS G|xNS
S ⊆ N |S| = m
xS G|xNS S T ⊊ S
xT G|xNT
xS G|xNS xS G|xNS
∀i ∈ S, ui(yS, xNS) ui(x)
G|xNS yS ∈ XS
͕݁ୗੑΛͭͱ
͕ ʹ͓͍ͯ
݁ୗੑΛͭ͜ͱΛ͍͏
x ∈ X x G
8. ݁ୗੑφογϡ֬ͱߧۉఆతઓུͷؔఆཧ
݁ୗੑφογϡ֬ͱߧۉఆతઓུΛͨͳ͍ ߧۉ
ઓུͷ ͕༩͑ΒΕ͍ͯΔ͜ͷͱ͖ҙͷ ʹ͍ͭͯ
͕෦ήʔϜ ʹ͓͍ͯ
݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
ʹ͓͍ͯͰ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ͱ͘ʹ
͕ ʹ͓͍ͯ݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
Ͱ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ؔ࿈ఆཧ
ڧφογϡߧۉ݁ୗੑΛͭ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
x ∈ X S ⊆ N xS ∈ XS G|xNS
T ⊆ S G|xNS x
x G T ⊆ N
x
x ∈ X S ⊆ N
G|xNS
9. ڧφογϡͳߧۉΒ݁ୗੑΛͭূ໌
݁ୗੑφογϡ֬ͱߧۉఆతઓུΛͨͳ͍ ߧۉ
ઓུͷ ͕༩͑ΒΕ͍ͯΔ͜ͷͱ͖ҙͷ ʹ͍ͭͯ
͕෦ήʔϜ ʹ͓͍ͯ
݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
ʹ͓͍ͯͰ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ͱ͘ʹ
͕ ʹ͓͍ͯ݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
Ͱ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ؔ࿈ఆཧ
ڧφογϡߧۉ݁ୗੑΛͭ
ূ໌
ઓུͷ Λڧφογϡ͢ͱߧۉΔ͜ͷͱ͖ڧφογϡߧۉͷఆٛΑΓ
ͲΜͳఏܞ Λߟ͑ͯʹ͓͍ͯઓུΛͨͳ͍
ઓུΛͨͳ͍ͷͳΒ
֬ఆతઓུͨͳ͍
Ώ͑ʹͲΜͳఏܞ Λߟ͑ͯ
ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍͜ͱΑΓ
ఆཧ͔Β݁ୗੑφογϡ͋ͰߧۉΔ
ূ໌ऴྃ
x ∈ X S ⊆ N xS ∈ XS G|xNS
T ⊆ S G|xNS x
x G T ⊆ N
x
x ∈ X
S ⊆ N x
S ⊆ N
x
ڧφογϡߧۉͷఆٛ
ઓུͷ ͕ڧφογϡ͋ͰߧۉΔͱɺ͍͔ͳΔఏܞ
ʹ͓͍ͯઓུΛͨͳ͍͜ͱΛ͍͏
x ∈ X S ⊆ N
x
֬ఆతઓུ
ΛۭͰͳ͍ҙͷఏ
ܞ Λҙʹ༩͑ΒΕͨઓུͷͱ͢Δ
͜ͷͱ͖
͕ʹ͓͍ͯ֬ఆతઓུ Λͭͱ
͕ઓུ
ͷͲͷਅ෦ू߹ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
S ⊆ N x ∈ X
S x yS ∈ XS
yS
S T ⊊ S (yS, xNS)
10. ݁ୗੑφογϡ֬ͱߧۉఆతઓུΛͨͳ͍ ߧۉ
ઓུͷ ͕༩͑ΒΕ͍ͯΔ͜ͷͱ͖ҙͷ ʹ͍ͭͯ
͕෦ήʔϜ ʹ͓͍ͯ
݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
ʹ͓͍ͯͰ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ͱ͘ʹ
͕ ʹ͓͍ͯ݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
Ͱ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
ূ໌
ςΩετ͔ΒͷҾ༻
Λ
ʹ͓͍ͯଞͷ͍͔ͳΔ֬ఆతઓུʹࢧ͞Εͳ͍֬ఆతઓུͱ͢Δ
͢Δͱ
ͲͷΑ͏ͳ෦ू߹ ෦ήʔϜ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
Ώ͑ʹ্ͷఆཧ͔Β ෦ήʔϜ ʹ͓͍ͯ݁ୗੑΛͭ
ɾɾɾʁͳ͔ͥཧղͰ͖ͳ͍ͳͥʁ
x ∈ X S ⊆ N xS ∈ XS G|xNS
T ⊆ S G|xNS x
x G T ⊆ N
x
x ∈ X S ⊆ N
G|xNS
yS ∈ XS S
T ⊊ S G|xNS
yS G|xNS
෦ήʔϜʹ͓͚Δ݁ୗੑφογϡߧۉͷଘࡏূ໌
12. ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
ূ໌
Λ
ʹ͓͍ͯଞͷ͍͔ͳΔ֬ఆతઓུʹࢧ͞Εͳ͍֬ఆతઓུͱ͢Δ
ఏܞΛߟ͑ͨ߹ͷࢧͷఆٛ
͕ Λࢧ͢Δͱ
ҙͷ ʹରͯ͠ ͱͳΔͱ͖Λ͍͏
͜ΕΛߟྀ͢Δͱ
ҙͷ ʹରͯ͠ ͱͳΔΑ͏ͳ
֬ఆతઓུ ͕ଘࡏ͠ͳ͍͜ͱʹͳΔ
x ∈ X S ⊆ N
G|xNS
yS ∈ XS S
y′
S ∈ XS yS ∈ XS xNS ∈ XNS ∀i ∈ S, ui(y′
S, xNS) ui(yS, xNS)
yS ∈ XS xNS ∈ XNS ∀i ∈ S, ui(y′
S, xNS) ui(yS, xNS)
y′
S ∈ XS
෦ήʔϜʹ͓͚Δ݁ୗੑφογϡߧۉͷଘࡏূ໌
N
S
yS
xNS
S
T yT
º
N
S
y′
S
xNS
S
T yT
º
S
S
yS
y′
S
Λࢧ͢ΔΑ͏ͳ
֬ఆతઓུ ͕ଘࡏ
yS ∈ XS
y′
S ∈ XS
֬ఆతઓུ
ΛۭͰͳ͍ҙͷఏ
ܞ Λҙʹ༩͑ΒΕͨઓུͷͱ͢Δ
͜ͷͱ͖
͕ʹ͓͍ͯ֬ఆతઓུ Λͭͱ
͕ઓུ
ͷͲͷਅ෦ू߹ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
S ⊆ N x ∈ X
S x yS ∈ XS
yS
S T ⊊ S (yS, xNS)
13. ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
ূ໌
Λ
ʹ͓͍ͯଞͷ͍͔ͳΔ֬ఆతઓུʹࢧ͞Εͳ͍֬ఆతઓུͱ͢Δ
ఏܞΛߟ͑ͨ߹ͷࢧͷఆٛ
͕ Λࢧ͢Δͱ
ҙͷ ʹରͯ͠ ͱͳΔͱ͖Λ͍͏
͜ΕΛߟྀ͢Δͱ
ҙͷ ʹରͯ͠ ͱͳΔΑ͏ͳ
֬ఆతઓུ ͕ଘࡏ͠ͳ͍͜ͱʹͳΔ
x ∈ X S ⊆ N
G|xNS
yS ∈ XS S
y′
S ∈ XS yS ∈ XS xNS ∈ XNS ∀i ∈ S, ui(y′
S, xNS) ui(yS, xNS)
yS ∈ XS xNS ∈ XNS ∀i ∈ S, ui(y′
S, xNS) ui(yS, xNS)
y′
S ∈ XS
෦ήʔϜʹ͓͚Δ݁ୗੑφογϡߧۉͷଘࡏূ໌
N
S
yS
xNS
S
T yT
º
N
S
y′
S
xNS
S
T yT
º
S
S
yS
y′
S
Λࢧ͢ΔΑ͏ͳ
֬ఆతઓུ ͕ଘࡏ
yS ∈ XS
y′
S ∈ XS
֬ఆతઓུ
ΛۭͰͳ͍ҙͷఏ
ܞ Λҙʹ༩͑ΒΕͨઓུͷͱ͢Δ
͜ͷͱ͖
͕ʹ͓͍ͯ֬ఆతઓུ Λͭͱ
͕ઓུ
ͷͲͷਅ෦ू߹ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
S ⊆ N x ∈ X
S x yS ∈ XS
yS
S T ⊊ S (yS, xNS)
Λࢧ͢ΔΑ͏ͳ
֬ఆతઓུ ͕ଘࡏ͠ͳ͍ͷͰ͋Ε
͜Ε෦ήʔϜ ʹ͓͍ͯ
͕֬ఆతઓུΛͨͳ͍͜ͱΛҙຯ͢Δ
yS ∈ XS
y′
S ∈ XS
G|xNS S
º
14. ݁ୗੑφογϡ֬ͱߧۉఆతઓུΛͨͳ͍ ߧۉ
ઓུͷ ͕༩͑ΒΕ͍ͯΔ͜ͷͱ͖ҙͷ ʹ͍ͭͯ
͕෦ήʔϜ ʹ͓͍ͯ
݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
ʹ͓͍ͯͰ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ͱ͘ʹ
͕ ʹ͓͍ͯ݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
Ͱ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
ূ໌
Λ
ʹ͓͍ͯଞͷ͍͔ͳΔ֬ఆతઓུʹࢧ͞Εͳ͍֬ఆతઓུͱ͢Δ
͜Ε෦ήʔϜ ʹ͓͍ͯ
͕ઓུΛͨͳ͍͜ͱΛҙຯ͢Δ
·ͨ
ͲͷΑ͏ͳ෦ू߹ ෦ήʔϜ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
͜Ε֬ఆతઓུͷఆٛΑΓ͑ݴΔ
x ∈ X S ⊆ N xS ∈ XS G|xNS
T ⊆ S G|xNS x
x G T ⊆ N
x
x ∈ X S ⊆ N
G|xNS
yS ∈ XS S
G|xNS S
T ⊊ S G|xNS
෦ήʔϜʹ͓͚Δ݁ୗੑφογϡߧۉͷଘࡏূ໌
֬ఆతઓུ
ΛۭͰͳ͍ҙͷఏ
ܞ Λҙʹ༩͑ΒΕͨઓུͷͱ͢Δ
͜ͷͱ͖
͕ʹ͓͍ͯ֬ఆతઓུ Λͭͱ
͕ઓུ
ͷͲͷਅ෦ू߹ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
S ⊆ N x ∈ X
S x yS ∈ XS
yS
S T ⊊ S (yS, xNS)
15. ݁ୗੑφογϡ֬ͱߧۉఆతઓུΛͨͳ͍ ߧۉ
ઓུͷ ͕༩͑ΒΕ͍ͯΔ͜ͷͱ͖ҙͷ ʹ͍ͭͯ
͕෦ήʔϜ ʹ͓͍ͯ
݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
ʹ͓͍ͯͰ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ͱ͘ʹ
͕ ʹ͓͍ͯ݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
Ͱ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
ূ໌
Λ
ʹ͓͍ͯଞͷ͍͔ͳΔ֬ఆతઓུʹࢧ͞Εͳ͍֬ఆతઓུͱ͢Δ
͜Ε෦ήʔϜ ʹ͓͍ͯ
͕ઓུΛͨͳ͍͜ͱΛҙຯ͢Δ
·ͨ
ͲͷΑ͏ͳ෦ू߹ ෦ήʔϜ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
͜Ε֬ఆతઓུͷఆٛΑΓ͑ݴΔ
͜ΕΒΑΓ
ͲͷΑ͏ͳ෦ू߹ ෦ήʔϜ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍ͨΊ
্هఆཧ͔Β
෦ήʔϜ ʹ͓͍ͯ
݁ୗੑΛͭ ূ໌ऴྃ
x ∈ X S ⊆ N xS ∈ XS G|xNS
T ⊆ S G|xNS x
x G T ⊆ N
x
x ∈ X S ⊆ N
G|xNS
yS ∈ XS S
G|xNS S
T ⊊ S G|xNS
T ⊆ S G|xNS
yS ∈ XS G|xNS
෦ήʔϜʹ͓͚Δ݁ୗੑφογϡߧۉͷଘࡏূ໌
16. ݁ୗੑφογϡ֬ͱߧۉఆతઓུͷؔఆཧ
݁ୗੑφογϡ֬ͱߧۉఆతઓུΛͨͳ͍ ߧۉ
ઓུͷ ͕༩͑ΒΕ͍ͯΔ͜ͷͱ͖ҙͷ ʹ͍ͭͯ
͕෦ήʔϜ ʹ͓͍ͯ
݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
ʹ͓͍ͯͰ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ͱ͘ʹ
͕ ʹ͓͍ͯ݁ୗੑφογϡ͋ͰߧۉΔͱ
ҙͷ෦ఏܞ ͕
Ͱ֬ఆతઓུΛͨͳ͍͜ͱͰ͋Δ
ؔ࿈ఆཧ
ڧφογϡߧۉ݁ୗੑΛͭ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
ؔ࿈ఆཧ ʹґଘͨ͠Ͱܗͷ
෦ήʔϜ ʹ͓͚Δ݁ୗੑφογϡ͋ͰߧۉΔ
x ∈ X S ⊆ N xS ∈ XS G|xNS
T ⊆ S G|xNS x
x G T ⊆ N
x
x ∈ X S ⊆ N
G|xNS
x ∈ X G|xNS
17. ݁ୗੑφογϡ֬ͱߧۉఆతઓུͷؔఆཧ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
x ∈ X S ⊆ N
G|xNS
AʘB
̌
AʘB
$͕
c1
a1
a2 a2
b1 b2 b1 b2
$͕
c2
a1
AʘB
AʘB
$͕
c1
a1
a2 a2
b1 b2 b1 b2
$͕
c2
a1
ͷઓུ
S = {A, B}
ͷ֬ఆతઓུ
S = {A, B}
ͷͱ͖෦ήʔϜ ʹ͓͍ͯ
݁ୗੑΛͭ
S = {A, B} G|xC
y{A,B} = (a2, b2)
18. ݁ୗੑφογϡ֬ͱߧۉఆతઓུͷؔఆཧ
ؔ࿈ఆཧ
ઓུͷ ʹ͓͍ͯ
֬ఆతઓུΛͭͱ͢Δ
͜ͷͱ͖
෦ήʔϜ ʹ͓͍ͯ݁ୗੑφογϡ͕ߧۉଘࡏ͢Δ
x ∈ X S ⊆ N
G|xNS
AʘB
AʘB
$͕
c1
a1
a2 a2
b1 b2 b1 b2
$͕
c2
a1
AʘB
AʘB
$͕
c1
a1
a2 a2
b1 b2 b1 b2
$͕
c2
a1
ͷઓུ
S = {C}
ͷ֬ఆతઓུ
S = {C}
ͷͱ͖෦ήʔϜ ʹ͓͍ͯ
݁ୗੑΛͭ
S = {C} G|x{A,B}
y{C} = (c2)
26. ෦ήʔϜ͕།ҰͷφογϡߧۉΛͭͱ͖
ఆཧ
ઓུͷ ͕༩͑ΒΕͨͱ͖
ͷۭͰͳ͍ҙͷ෦ू߹ ʹ͍ͭͯ
෦ήʔϜ །ҰͷφογϡߧۉΛͭͱ͢Δͱ
ͷ݁ୗੑφογϡ͋ͰߧۉΔ
ূ໌
ͷͱ͖Λߟ͑Δ෦ήʔϜ Ͱ͋Δ͔Β
ԾఆΑΓ
ͷ།Ұͷφογϡ͋ͰߧۉΔ
·ͨ
͍͔ͳΔ෦ू߹ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍
࣮ࡍ
Λߟ͑Δ͜Ε͕ʹ͓͚Δઓུͱ͢Δ
Ծఆ͔Β
෦ήʔϜ ʹ͓͚Δ།Ұͷφογϡ͋ͰߧۉΔͨΊ
φογϡͰߧۉͳ͍
͢Δͱ
͋ΔϓϨΠϠʔ ʹ͍ͭͯ ʹ͓͍ͯઓུ
ਓఏͳܞͷͰ
͢ͳΘͪ֬ఆతઓུΛͭ
֬ఆతͰͳ͍
Ώ͑ʹ
͍͔ͳΔ෦ू߹ ʹ͓͍ͯ֬ఆతઓུΛͨͳ͍ͷ͔ͩΒ
݁ୗੑφογϡ͋ͰߧۉΔ
ʢূ໌ऴྃ
x ∈ X N S ⊆ N
G|xNS x G
S = N G|xNN = G
x ∈ X G
S ⊆ N x
yS ≠ xS x
xS G|xNS
yS
i ∈ S (yS, xNS)
yS
S ⊆ N x x
N x
N x
S S
yS i y′
{i}