Stochastic wave equations driven by space-time $G$-white noise under sublinear expectation

In this paper, we study one-dimensional semilinear stochastic wave equations driven by multiplicative space-time $G$-white noise under sublinear expectation. We establish the existence and uniqueness of global mild solutions. By developing the quadratic variation structure of space-time $G$-white noise and establishing a Burkholder-Davis-Gundy inequality for the associated stochastic integrals, we derive higher-order moment estimates and prove the quasi-sure Hölder continuity of the solutions. We further show that the mild solution satisfies the corresponding weak formulation.