Idempotents as J-projections: II

Abstract

Let B(H) Id be the set of all bounded idempotents on a complex Hilbert space H and let J be a conjugation operator on H. Fix p ∈ B(H) Id. At the paper we describe of J-projections. We prove that for a given p there exists a conjugation operator J 0 such that p is a J 0-projection. © 2012 Pleiades Publishing, Ltd.