Abstract. A class of semilinear evolution equations of the second order in time of the form u tt + Au + µAu t + Au tt = f (u) is considered, where −A is the Dirichlet Laplacian, Ω is a smooth bounded domain in R N and f ∈ C 1 (R, R). A local well posedness result is proved in the Banach spaces Wwhen f satisfies appropriate critical growth conditions. In the Hilbert setting, if f satisfies an additional dissipativeness condition, the nonlinear semigroup of global solutions is shown to possess a gradient-like attractor. Existence and regularity of the global attractor are also investigated following the unified semigroup approach, bootstrapping and the interpolation-extrapolation techniques.
Introductory notesIn this article we consider a class of semilinear evolution equations of the second order in time of the form (1.1)with the initial conditionsfrom a suitably chosen Banach space X 1 . Here −A : D(A) ⊂ X → X is the generator of an exponentially decaying analytic semigroup of bounded linear operators in X and X 1 is the domain of A with the graph norm. The equations that fall into this class are known to represent some sort of 'propagation problems' (see [4,6,22]; also [19] and the references therein), among which a specific problem is Key words and phrases. Evolution equations of the second order in time, existence, uniqueness and continuous dependence of solutions on initial conditions, asymptotic behavior of solutions, attractors, regularity, critical exponents.