Counterexamples undeniably play an outstanding role in mathematics. As is known,
counterexamples are patently examples but with a different purpose. The commonly agreed …

This book is for third and fourth year university mathematics students (and Master students)
as well as lecturers and tutors in mathematics and anyone who needs the basic facts on …

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 …

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 …

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 …

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 …

EUDML | Generalizations of Kaplansky's Theorem Involving Unbounded Linear Operators Skip
to main content (access key 's'), Skip to navigation (access key 'n'), Accessibility information …

The present paper discusses Weiss' version of the Fuglede–Putnam theorem. We establish
three generalizations of this version, each of which involves unbounded normal operators …

ON THE COMMUTATIVITY OF UNBOUNDED UNCLOSED SYMMETRIC OPERATORS 1.
Introduction First, we assume readers are well acquainted with Page 1 ON THE …

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 …