math.DS — Dynamical Systems
Finiteness of Planar Central Configurations for Five Positive Masses
We prove that, for any five positive masses, there are finitely many planar Newtonian central configurations up to translations, rotations, and positive scaling. Building on the singular-diagram framework of Albouy and Kaloshin, we treat the exceptional masses left open by their finiteness theorem. The proof retains a lower bound for the physical potential after passing to the complex algebraic equations. On each fixed potential level, energy estimates, torque identities, and local response calculations control the possible degenerations. A polynomial selection argument then yields finiteness. The exceptional local calculations and their algebraic certificates are given explicitly. A separate Lean development accompanies the proof.