منابع مشابه
A Characterization of Convex Functions and Its Application to Operator Monotone Functions
We give a characterization of convex functions in terms of difference among values of a function. As an application, we propose an estimation of operator monotone functions: If A > B ≥ 0 and f is operator monotone on (0,∞), then f(A)−f(B) ≥ f(‖B‖+ )−f(‖B‖) > 0, where = ‖(A−B)−1‖−1. Moreover it gives a simple proof to Furuta’s theorem: If logA > logB for A, B > 0 and f is operator monotone on (0...
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The notions of a quasi-monotone operator and of a cyclically quasi-monotone operator are introduced, and relations between such operators and quasi-convex functions are established.
متن کاملOperator monotone functions and Löwner functions of several variables
We prove generalizations of Löwner’s results on matrix monotone functions to several variables. We give a characterization of when a function of d variables is locally monotone on d-tuples of commuting self-adjoint n-by-n matrices. We prove a generalization to several variables of Nevanlinna’s theorem describing analytic functions that map the upper half-plane to itself and satisfy a growth con...
متن کاملOperator monotone functions of several variables
We propose a notion of operator monotonicity for functions of several variables, which extends the well known notion of operator monotonicity for functions of only one variable. The notion is chosen such that a fundamental relationship between operator convexity and operator monotonicity for functions of one variable is extended also to functions of several variables.
متن کاملApplication of operator monotone functions in economics
Operator monotone functions play an important role in economics. We show that 2-monotonicity is equivalent to decreasing relative risk premium, a notion recently introduced in microeconomics. We also show that an operator monotone function is risk vulnerable, a notion introduced by Gollier and Pratt.
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ژورنال
عنوان ژورنال: Annales Polonici Mathematici
سال: 1995
ISSN: 0066-2216,1730-6272
DOI: 10.4064/ap-62-1-1-11