42 research outputs found
Optimal control of fractional semilinear PDEs
In this paper we consider the optimal control of semilinear fractional PDEs
with both spectral and integral fractional diffusion operators of order
with . We first prove the boundedness of solutions to both
semilinear fractional PDEs under minimal regularity assumptions on domain and
data. We next introduce an optimal growth condition on the nonlinearity to show
the Lipschitz continuity of the solution map for the semilinear elliptic
equations with respect to the data. We further apply our ideas to show
existence of solutions to optimal control problems with semilinear fractional
equations as constraints. Under the standard assumptions on the nonlinearity
(twice continuously differentiable) we derive the first and second order
optimality conditions
A note on semilinear fractional elliptic equation: analysis and discretization
In this paper we study existence, regularity, and approximation of solution
to a fractional semilinear elliptic equation of order . We
identify minimal conditions on the nonlinear term and the source which leads to
existence of weak solutions and uniform -bound on the solutions. Next
we realize the fractional Laplacian as a Dirichlet-to-Neumann map via the
Caffarelli-Silvestre extension. We introduce a first-degree tensor product
finite elements space to approximate the truncated problem. We derive a priori
error estimates and conclude with an illustrative numerical example
External optimal control of fractional parabolic PDEs
In this paper we introduce a new notion of optimal control, or source
identification in inverse, problems with fractional parabolic PDEs as
constraints. This new notion allows a source/control placement outside the
domain where the PDE is fulfilled. We tackle the Dirichlet, the Neumann and the
Robin cases. For the fractional elliptic PDEs this has been recently
investigated by the authors in \cite{HAntil_RKhatri_MWarma_2018a}. The need for
these novel optimal control concepts stems from the fact that the classical PDE
models only allow placing the source/control either on the boundary or in the
interior where the PDE is satisfied. However, the nonlocal behavior of the
fractional operator now allows placing the control in the exterior. We
introduce the notions of weak and very-weak solutions to the parabolic
Dirichlet problem. We present an approach on how to approximate the parabolic
Dirichlet solutions by the parabolic Robin solutions (with convergence rates).
A complete analysis for the Dirichlet and Robin optimal control problems has
been discussed. The numerical examples confirm our theoretical findings and
further illustrate the potential benefits of nonlocal models over the local
ones.Comment: arXiv admin note: text overlap with arXiv:1811.0451