From: Groupwise information sharing promotes ingroup favoritism in indirect reciprocity
Rule
p in ∗ (G)
p out ∗ (G)
Stability condition
ψ
ρ
IM
1 2
Unstable
0
ST
1−μ
1−μ 1 + θ θ +O( μ 2 )
Eq. (14)
1− μ θ +O( μ 2 )
μ θ +O( μ 2 )
JG
Eq. (18)
1 + θ 2 −μθ
1 2 −μ