(Color online) The width of the ESPPs with ϕ ( 1 ) > 0 for u 0 = 0.01 , δ = 15, σ = 0.25, κ 1 = 20 , κ 2 = 3 , α = 0.5, μ = 0.65 (dashed curve), μ = 0.75 (solid curve), and μ = 0.90 (dotted curve).