“Destruction” of the solution of a strongly nonlinear equation of pseudoparabolic type with double nonlinearity

We consider the first initial-boundary value problem for multidimensional strongly nonlinear equations with double nonlinearity of pseudoparabolic type in a bounded domain with sufficiently smooth boundary. We prove the local solvability of this problem in the weak generalized sense. Depending on the nonlinearity and initial conditions under consideration, we prove the solvability of the equation in any finite cylinder $(x,t)\in\Omega\times[0,T]$ or the destruction of the solution in finite time.