The Dirichlet-to-Neumann map, the boundary Laplacian, and Hörmander's rediscovered manuscript

Alexandre Girouard, Mikhail Karpukhin, Michael Levitin +1

How close is the Dirichlet-to-Neumann (DtN) map to the square root of the corresponding boundary Laplacian? This question has been actively investigated in recent years. Somewhat s…