Category Archives: Functional analysis

Square root lemma

This post is a continuation of Positive operators II, We begin by recalling the main fact proved there, then explain how a classical binomial series leads to a functional calculus for the square root of a positive operator. Corollary  1 … Continue reading

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Positive operators II

This post is a continuation of Positive operators I. The aim here is to explain how the norm of a bounded self–adjoint operator can be expressed in terms of the associated quadratic form. We will first recall the Riesz representation … Continue reading

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Complexification of a Real Krein Space. Part I

Introduction There is a rather unusual journal called the Journal of Humanistic Mathematics. It aims to provide an open forum for academic and informal discussions of the “human face of mathematics,” focusing on aesthetic, cultural, historical, literary, pedagogical, philosophical, psychological, … Continue reading

Posted in Functional analysis, Krein spaces, Linear Algebra, Lorentz transforations, Quaternions, Special relativity | Tagged , , , , | 6 Comments