A criterion for the normality of unbounded operators and applications to self-adjointness. (English) Zbl 1333.47019
Authors’ abstract: We give and prove a criterion for the normality of unbounded closed operators, which is a sort of a maximality result which will be called “double maximality”. As applications, we show, under some assumptions, that the sum of two symmetric operators is essentially self-adjoint; and that the sum of two unbounded normal operators is essentially normal. Some other important results are also established.
Reviewer: Kun Soo Chang (Seoul)
MSC:
| 47B25 | Linear symmetric and selfadjoint operators (unbounded) |
| 47A05 | General (adjoints, conjugates, products, inverses, domains, ranges, etc.) |
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