Products of Positive Operators

Abstract On finite dimensional spaces, it is apparent that an operator the product of two positive operators if and only similar to a operator. Here, class $${\mathcal {L}^{+\,2}}$$ L + 2 bounded on separable infinite Hilbert spaces which can be written as studied. The structure much richer, connects (but not equivalent to) quasi-similarity quasi-affinity spectral properties in are developed, membership among special classes, including algebraic compact operators, examined.