“…(Necessity) Suppose {û i , i = 1, • • • , N} is a set of social optimal strategies, and{x i , i = 1, • • • , N } is the corresponding states of agents. Let { λi , βj i , i, j = 1, • • • , N} be a set of solutions to the second equation of(42). For any u i ∈ U d,i and θ ∈ R (θ = 0), let u θ i = ûi + θv i .…”