Weak Saturation of the 3-Cube in Complete Graphs: Exact Values at Orders 9, 10, 11

We determine the weak saturation number of the three-dimensional cube Q_3in complete graphs at orders 9, 10, and 11. We prove wsat(K₉, Q₃) = 16, wsat(K₁₀, Q₃) = 18, wsat(K₁₁, Q₃) = 19. The upper bounds are established by explicit weak-saturation certificates.The lower bounds are established by exhaustive finite closure computations,including symmetry reduction for the larger instances. The computationalverification is accompanied by machine-readable certificates, independentverification programs, orbit representatives, closure data, andreproducibility records. The computational source code and exact paper-version repository areavailable at: https://github.com/Vedansh-Saha/weak-saturation-q3 The GitHub repository contains the computational materials correspondingto this preprint.