In this paper‎, ‎we study some properties of analytic extension of a $n$th roots of $M$-hyponormal operator‎. ‎We show that every analytic extension of a $n$th roots of $M$-hyponormal operator is subscalar of order $2k+2n$‎. ‎As a consequence‎, ‎we get that if the spectrum of such operator $T$ has a nonempty interior in $mathbb{C}$‎, ‎then $T$ has a nontrivial invariant subspace‎. ‎Finally‎, ‎w...

in this paper‎, ‎we study some properties of analytic extension of a $n$th roots of $m$-hyponormal operator‎. ‎we show that every analytic extension of a $n$th roots of $m$-hyponormal operator is subscalar of order $2k+2n$‎. ‎as a consequence‎, ‎we get that if the spectrum of such operator $t$ has a nonempty interior in $mathbb{c}$‎, ‎then $t$ has a nontrivial invariant subspace‎. ‎finally‎, ‎w...

In this paper it is shown that if T ∈ L(H) satisfies (i) T is a pure hyponormal operator; (ii) [T ∗, T ] is of rank-two; and (iii) ker [T ∗, T ] is invariant for T , then T is either a subnormal operator or the Putinar’s matricial model of rank two. More precisely, if T |ker [T∗,T ] has the rank-one self-commutator then T is subnormal and if instead T |ker [T∗,T ] has the ranktwo self-commutato...

In 1984 M. Putinar proved that hyponormal operators are subscalar operators of order two. The proof provided a concrete structure of such operators. We will use this structure to give a sufficient condition for hyponormal operators T with trace-class commutator to admit a direct summand S so that T ⊕ S is the sum of a normal operator and a HilbertSchmidt operator. We investigate what this suffi...

For Hilbert space operators A and B, let δAB denote the generalised derivation δAB(X) = AX − XB and let 4AB denote the elementary operator4AB(X) = AXB−X. If A is a pk-quasihyponormal operator, A ∈ pk−QH, and B∗ is an either p-hyponormal or injective dominant or injective pk−QH operator (resp., B∗ is an either p-hyponormal or dominant or pk −QH operator), then δAB(X) = 0 =⇒ δA∗B∗(X) = 0 (resp., ...

In this paper, we show that for a hyponormal operator the analytic spectral subspace coincides with the algebraic spectral subspace. Using this result, we have the following result: Let T be a operator with property (δ) on a Banach space X and let S be a hyponormal operator on a Hilbert space H. Then every generalized intertwining linear operator θ : X → H for (S, T ) is continuous if and only ...

Firstly, we will show the following extension of the results on powers of p-hyponormal and log-hyponormal operators: let n andm be positive integers, if T is p-hyponormal for p ∈ (0,2], then: (i) in case m ≥ p, (Tn+mTn+m)(n+p)/(n+m) ≥ (TnTn)(n+p)/n and (TnTn ∗ )(n+p)/n ≥ (Tn+mTn+m)(n+p)/(n+m) hold, (ii) in case m < p, Tn+mTn+m ≥ (Tn ∗ Tn)(n+m)/n and (TnTn ∗ )(n+m)/n ≥ Tn+mTn+m hold. Secondly, w...

We prove an n-tuple analogue of the Putnam area inequality for the spectrum of a single p-hyponormal operator. Let B…H† denote the algebra of operators (i.e. bounded linear transformations) on a separable Hilbert space H. The operator A 2 B…H† is said to be p-hyponormal, 0 < p 1, if jA j2p jAj2p. Let H…p† denote the class of p-hyponormal operators. Then H…1† consists of the class of p-hyponorma...

A sufficient condition is obtained for two isometries to be unitarily equivalent. Also, a new class of M-hyponormal operator is constructed