[图书][B] Counterexamples in operator theory
MH Mortad - 2022 - Springer
Counterexamples undeniably play an outstanding role in mathematics. As is known,
counterexamples are patently examples but with a different purpose. The commonly agreed …
counterexamples are patently examples but with a different purpose. The commonly agreed …
Certain properties involving the unbounded operators p (T), TT⁎, and T⁎ T; and some applications to powers and nth roots of unbounded operators
MH Mortad - Journal of Mathematical Analysis and Applications, 2023 - Elsevier
In this paper, we are concerned with conditions under which [p (T)]⁎= p‾(T⁎), where p (z) is
a one-variable complex polynomial, and T is an unbounded, densely defined, and linear …
a one-variable complex polynomial, and T is an unbounded, densely defined, and linear …
Conditions implying commutativity of unbounded self-adjoint operators and related topics
K Gustafson, MH Mortad - Journal of Operator Theory, 2016 - JSTOR
Let B be a bounded self-adjoint operator and let A be a nonnegative self-adjoint unbounded
operator. It is shown that if BA is normal, it must be self-adjoint and so must be AB …
operator. It is shown that if BA is normal, it must be self-adjoint and so must be AB …
Maximality of linear operators
M Meziane, MH Mortad - Rendiconti del Circolo Matematico di Palermo …, 2019 - Springer
Maximality of linear operators | SpringerLink Skip to main content Advertisement SpringerLink
Account Menu Find a journal Publish with us Search Cart 1.Home 2.Rendiconti del Circolo …
Account Menu Find a journal Publish with us Search Cart 1.Home 2.Rendiconti del Circolo …
The Fuglede theorem and some intertwining relations
IFZ Bensaid, S Dehimi, B Fuglede… - Advances in Operator …, 2021 - Springer
In this paper, we show new versions of the Fuglede theorem in an unbounded setting. A
related counterexample is also presented. In the second part of the paper, we give a pair of …
related counterexample is also presented. In the second part of the paper, we give a pair of …
[HTML][HTML] Commutativity up to a factor for bounded and unbounded operators
C Chellali, MH Mortad - Journal of Mathematical Analysis and Applications, 2014 - Elsevier
In this paper, we further investigate the problem of commutativity up to a factor (or λ-
commutativity) in the setting of bounded and unbounded linear operators in a complex …
commutativity) in the setting of bounded and unbounded linear operators in a complex …
On generalized powers of operators
On generalized powers of operators | Rendiconti del Circolo Matematico di Palermo Series
2 Skip to main content SpringerLink Account Menu Find a journal Publish with us Track your …
2 Skip to main content SpringerLink Account Menu Find a journal Publish with us Track your …
Unbounded generalizations of the Fuglede-Putnam theorem and applications to the commutativity of self-adjoint operators
In this article, we prove and disprove several generalizations of unbounded versions of the
Fuglede-Putnam theorem. As applications, we give conditions guaranteeing the …
Fuglede-Putnam theorem. As applications, we give conditions guaranteeing the …
Some Applications
MH Mortad - The Fuglede-Putnam Theory, 2022 - Springer
In the beginning, why “some” applications only? The answer is pretty simple. The Fuglede
theorem's applications are abundant and cannot all be included in this survey. Recall that …
theorem's applications are abundant and cannot all be included in this survey. Recall that …