Analytic results on Kepler-223 from Equations (6), (10), and (11), with panels (a), (b), and (c) showing the regions in (α, β) space with convergent migration between planet b and triplet c–d–e, between pair b–c and pair d–e, and between triplet b–c–d and planet e, respectively, and panel (d) showing the combined result from the overlap of panels (a)–(c). Red indicates convergent outward migration, and blue indicates convergent inward migration. Panel (d) shows that the Kepler-223 resonant chain cannot be sustained by inward migration and that the convergent outward migration zone does not include the steady-state, constant α _ν -viscosity disk models (dashed line).