2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204408We regard binary black hole (BBH) merger as a map from a simple initial state (two Kerr black holes, with dimensionless spins {\bf a} and {\bf b}) to a simple final state (a Kerr black hole with mass m, dimensionless spin {\bf s}, and kick velocity {\bf k}). By expanding this map around {\bf a} = {\bf b} = 0 and applying symmetry constraints, we obtain a simple formalism that is remarkably successful at explaining existing BBH simulations. It also makes detailed predictions and suggests a more efficient way of mapping the parameter space of binary black hole merger. Since we rely on symmetry rather than dynamics, our expansion complements previous analytical techniques.4 pages, 4 figures, matches Phys. Rev. Lett. versionGeneral Relativity and Quantum CosmologyAstrophysicsHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext