Convergence rates for SDP discretizations
Establish convergence rates for the finite-dimensional semidefinite-programming discretizations of the infinite-dimensional Lagrange dual problem, potentially by proving higher-than-$H^1$ regularity for the optimal dual variable and the critical fields associated with the positive-sem definiteness constraint.
References
First, although we have proved that SDP discretizations of the dual problem \cref{e:ldp} converge, we have no convergence rates. Our computations suggest that classical approximation rates for Galerkin methods should apply. Proving this, however, requires a higher than $H1$ regularity for the optimal dual variable $\xi$ and for the `critical fields' associated with the constraint of \cref{e:ldp}.
A second open challenge is to remove the computational bottlenecks in the solution of high-resolution SDP discretizations of \cref{e:ldp}.