2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/122782We address the self-similar solvability of a singular parabolic problem and show that solutions to parabolic fully nonlinear equations are not expected to be $C^{2,1}$.15 pages, 5 figuresAnalysis of PDEs35K55A counterexample to $C^{2,1}$ regularity for parabolic fully nonlinear equationstext