“…Finus and Rundshagen (2001), Rubio and Casino (2001) and De Cara and Rotillon (2001) have independently proved that the self-enforcing IEA consists of at most two countries in the quadratic basic model of the literature, (22). From (20) and (22) follows that if a stable coalition of size m = 2 exists [does not exist] in the economy defined by the parameters (β,δ,ρ) in (22), it also exists [does not exist] in every economy (α, β, γ, δ) ∈ E(β,δ,ρ), where E(β,δ,ρ) := (α, β, γ, δ) ∈ R 4 + β =β, δ =δ and α + γ =ρ .…”