Frame completions with prescribed norms: local minimizers and applications (Q1696373)

This paper describes some features of local minimizers of convex potentials within the set of frame completions with prescribed norms, the approach of which is based on a local Lidskii's theorem. It also proves that that minimizers of strictly convex potentials within the set of frame completions with prescribed norms are also global minimizers, which are then applied to prove (a generalized version of) Strawn's conjecture on local minima of the frame operator distance.