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

In this paper, we are mainly concerned with studying arbitrary unbounded square roots of
linear operators as well as some of their basic properties. The paper contains many …

We have already introduced the concept of commutativity of a bounded operator with an
unbounded one. In the case of two densely defined operators A and B, things are more …

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