I moved the section on affiliated operators from unbounded operator to a new section in the recent entry affiliated operator.

]]>I see that in a different way, some of the things overlap with unbounded operator which has been recently much expanded into sections on specialized notions which often deserve their own pages (by whom?).

]]>Bounded self-adjoint operators make an algebra, and once can put that into the dagger category setup, however the unbounded operators do not form algebras under composition, hence one needs to be more careful. I removed the redirects and opened a new entry self-adjoint operator redirecting also adjoint operator. This is in part prompted by the discussion in parallel entry on the need and no need for the domain of the definition. The matter is not that simple, but sometimes one can avoid domain discussion for some questions. We need to be more precise one when it is important and when and how one can avoid it.

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