Notes. ^(a) Here the parameters denote −m_d2/m_d1: the mass ratio between planet d₂ and d₁ before merging, t_{a, I}: semi-major axis damping timescale in the disk phase, t_{a, I}/t_{e, I}: the ratio between semi-major axis damping and eccentricity damping timescale in disk phase, t_d: the disk dispersal timescale, Δa/a: the instantaneous kick applied to the semi-major axis of planet d2 to break the resonances, Q_{phy, x}: the effective tidal damping parameter for planet x (see Section 2.3), t_{a 0, III}^b, t_{a0, IV}^b: the equivalent semi-major axis migration timescale due to torque on planet b in Phase III and Phase IV, t_{Γ, II}^b, t_{Γ, IV}^b: the exponential decay timescale of the torque on planet b in Phase III and Phase IV, P_d/P_c: the period ratio of planet c and d after planet merging.