𝔖 Bobbio Scriptorium
✦   LIBER   ✦

The Extreme Points of Order Intervals of Positive Operators

✍ Scribed by W.L. Green; T.D. Morley


Publisher
Elsevier Science
Year
1994
Tongue
English
Weight
433 KB
Volume
15
Category
Article
ISSN
0196-8858

No coin nor oath required. For personal study only.

✦ Synopsis


Consider the order interval of operators ([0, A}={X \mid 0 \leq X \leq A}). In finite dimensions (or if (A) is invertible) then the extreme points of ([0, A]) are the shorted operators (generalized Schur complements) of (A). This is false in the general infinite dimensional case. We give an example arising from the discretization of the biharmonic equation. We also give necessary and sufficient conditions for an extreme point (X_{0}) to be a short of (A, 1994) Academic Press, Inc.


πŸ“œ SIMILAR VOLUMES


Extreme point results for robust stabili
✍ B.R. Barmish; H.I. Kang πŸ“‚ Article πŸ“… 1992 πŸ› Elsevier Science 🌐 English βš– 959 KB

The Alternating Hurwitz Minor Condition (AHMC) provides new extreme point results for robust stability of convex combination of two polynomials which have an impact on robust stability of feedback systems involving interval plants.

Three positive fixed points of nonlinear
✍ R.I. Avery; A.C. Peterson πŸ“‚ Article πŸ“… 2001 πŸ› Elsevier Science 🌐 English βš– 331 KB

We generalize the fixed-point theorem of Leggett-Williams, which is a theorem giving conditions that imply the existence of three fixed points of an operator defined on a cone in a Banach space. We then show how to apply our theorem to prove the existence of three positive solutions to a second-orde

Shape Preserving Properties of Some Posi
✍ Ingrid Carbone πŸ“‚ Article πŸ“… 1998 πŸ› Elsevier Science 🌐 English βš– 265 KB

In this paper we study some shape preserving properties of particular positive linear operators acting on spaces of continuous functions defined on the interval [0, + [, which are strongly related to the semigroups generated by a large class of degenerate elliptic second order differential operators