Factoring a Quadratic Operator as a Product of Two Positive Contractions
Chi-Kwong Li, Ming-Cheng Tsai · Canadian Mathematical Bulletin · 2015
Abstract Let T be a quadratic operator on a complex Hilbert space H. We show that T can be written as a product of two positive contractions if and only if T is of the form for some a, b ∊ [0, 1] and strictly positive operator P with . Also, we give a necessary condition for a bounded linear operator T with operator matrix on H⊕K that can be written as a product of two positive contractions.