Global attractors for nonlinear viscoelastic equations with memory

We study the asymptotic properties of the semigroup S(t) arising from a nonlinear viscoelastic equation with hereditary memory on a bounded three-dimensional domain written in the past history framework of Dafermos. We establish the existence of the global attractor of optimal regularity for S(t) for a wide class of nonlinearities as well as within the most general condition on the memory kernel

On the behavior of solutions to Schr\"odinger equations with dipole-type potentials near the singularity

Asymptotics of solutions to Schroedinger equations with singular dipole-type potentials is investigated. We evaluate the exact behavior near the singularity of solutions to elliptic equations with potentials which are purely angular multiples of radial inverse-square functions. Both the linear and the semilinear (critical and subcritical) cases are considered

A minimal time optimal control for a drone landing problem

We study a variant of the classical safe landing optimal control problem in aerospace engineering, introduced by Miele (1962), where the target was to land a spacecraft on the moon by minimizing the consumption of fuel. A more modern model consists in replacing the spacecraft by a hybrid gas-electric drone. Assuming that the drone has a failure and that the thrust (representing the control) can act in both vertical directions, the new target is to land safely by minimizing time, no matter of what the consumption is. In dependence of the initial data (height, velocity, and fuel), we prove that the optimal control can be of four different kinds, all being piecewise constant. Our analysis covers all possible situations, including the nonexistence of a safe landing strategy due to the lack of fuel or for heights/velocities for which also a total braking is insufficient to stop the drone

Wave equations with memory: the minimal state approach

AbstractRecently, in M. Conti et al. (2010) [6] and M. Fabrizio et al. (2010) [12], a new theoretical scheme has been developed in order to study equations with memory, the so-called minimal state approach. The aim of this work is to provide the technical body needed to study the asymptotic behavior of semilinear integro-differential equations of hyperbolic type in the novel framework

On Schrödinger operators with multisingular inverse-square anisotropic potentials

none3We study positivity, localization of binding and essential self-adjointness properties of a class of Schrödinger operators with many anisotropic inverse square singularities, including the case of multiple dipole potentials.V. FELLI; E. MARCHINI; S. TERRACINIV., Felli; Marchini, ELSA MARIA; S., Terracin