TY - JOUR ID - Fischbacher2021 LB - Fischbacher2021 AU - Fischbacher, Christoph TI - Extensions of dissipative operators with closable imaginary part ST - Extensions of dissipative operators with closable imaginary part JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2021 VL - 41 IS - 3 SP - 381 EP - 393 DO - https://doi.org/10.7494/OpMath.2021.41.3.381 UR - https://doi.org/10.7494/OpMath.2021.41.3.381 AB - Given a dissipative operator \(A\) on a complex Hilbert space \(\mathcal{H}\) such that the quadratic form \(f \mapsto \text{Im}\langle f, Af \rangle\) is closable, we give a necessary and sufficient condition for an extension of \(A\) to still be dissipative. As applications, we describe all maximally accretive extensions of strictly positive symmetric operators and all maximally dissipative extensions of a highly singular first-order operator on the interval. KW - extension theory KW - dissipative operators KW - ordinary differential operators SN - 1232-9274 ER -