Global Existence and Blow-up in Finite Time for a Class of Finitely Degenerate Semilinear Pseudo-parabolic Equations

In this paper, we study the initial-boundary value problem for the semilinear pseudoparabolic equations u-△Xu-△Xu = |u|u, where X =(X, X,..., X) is a system of real smooth vector fields which satisfy the H?rmander’s condition, and △X = ∑~m X~2 is a finitely degenerate elliptic operator. By using potential well method, we first prove the invariance of some sets and vacuum isolating of solutions. Then, by the Galerkin method and the concavity method we show the global existence and blow-up in finite time of solutions with low initial energy or critical initial energy.The asymptotic behavior of the global solutions and a lower bound for blow-up time of local solution are also given.