2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/134604This paper establishes the optimal decay rate for scalar oscillatory integrals in $n$ variables which satisfy a nondegeneracy condition on the third derivatives. The estimates proved are stable under small linear perturbations, as encountered when computing the Fourier transform of surface-carried measures. The main idea of the proof is to construct a nonisotropic family of balls which locally capture the scales and directions in which cancellation occurs.22 pages; v2 added referencesClassical Analysis and ODEstext