73 citations · 75 across the 4 of their papers we have counts for
4 papers
Natural Isomorphism from a Linear Map's Image to Complement of Nullspace
H. N. Friedel
There is a natural isomorphism from image to complement of nullspace, for a bounded linear map from a real Banach space onto a closed subspace of a real Hilbert space. This general…
Self-Adjoint Extension of Symmetric Maps
H. N. Friedel
A densely-defined symmetric linear map from/to a real Hilbert space extends to a self-adjoint map. Extension is expressed via Riesz representation. For a case including Friedrichs…
Short Proof of Dirichlet's Principle
H. N. Friedel
A standard Hilbert-space proof of Dirichlet's principle is simplified, using an observation that a certain form of min-problem has unique solution, at a specified point. This solve…
Adaptive Mesh Refinement for Singular Current Sheets in Incompressible Magnetohydrodynamic Flows
Holger Friedel, Rainer Grauer, Christiane Marliani
The formation of current sheets in ideal incompressible magnetohydrodynamic flows in two dimensions is studied numerically using the technique of adaptive mesh refinement. The grow…