On a criterion of mutual adjointness for extensions of some nondensely defined operators. (English) Zbl 1313.47005

Let \(L_0,M_0\) be a pair of closed densely defined linear operators on a Hilbert space, such that \(L_0\subset M_0^*\). The authors find a criterion for mutual adjointness for some classes of extensions of finite dimensional nondensely defined restrictions of \(L_0\) and \(M_0\). The results are formulated in terms of abstract boundary conditions.


47A05 General (adjoints, conjugates, products, inverses, domains, ranges, etc.)
47A06 Linear relations (multivalued linear operators)