RT journal article T1 The adjoint of an operator on a Banach space A1 García Pacheco, Francisco Javier A2 Matemáticas K1 Duality mapping K1 Probability density operator K1 Probability density operator K1 Smooth Banach space AB Self-adjoint operators in smooth Banach spaces have been already defined in recent works. Here, we extend the concept of adjoint of an operator to the scope of (non-necessarily Hilbert) Banach spaces, obtaining in particular the notion of self-adjoint operator in the non-smooth case. As a consequence, we define the probability density operator on Banach spaces and verify most of its well-known properties. PB Springer SN 0010-0757 YR 2023 FD 2023-08-21 LK http://hdl.handle.net/10498/31355 UL http://hdl.handle.net/10498/31355 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 12-nov-2026