We discuss the possibility to represent smooth nonnegative matrix-valued functions as finite linear combinations of fixed matrices with positive real-valued coefficients whose square roots are Lipschitz continuous. This issue is reduced to a similar problem for smooth functions with values in a polyhedron.
Bibliographical noteFunding Information:
The work was partially supported by NSF Grant DMS-0653121.
- Diagonally dominant matrices
- Finite-difference approximations