From Encyclopedia of Mathematics - Reading time: 1 min
of a symmetric operator
The operators (the closure of , cf. Closed operator) and (the adjoint of , cf. Adjoint operator), respectively. All closed symmetric extensions of occur between these. Equality of the maximal and minimal extensions is equivalent to the self-adjointness of (cf. Self-adjoint operator) and is a necessary and sufficient condition for the uniqueness of a self-adjoint extension.
References[edit]
[a1] | M. Reed, B. Simon, "Methods of modern mathematical physics" , 1. Functional analysis , Acad. Press (1972) pp. Chapt. 8 |