Locating the Range of an Operator on a Hilbert Space
Douglas Bridges, Hajime Ishihara · Bulletin of the London Mathematical Society · 1992
In classical operator theory it is taken for granted that we can project onto the closure of the range of an operator T on a Hilbert space H. In a constructive development of operator theory, to which this note is a contribution, this projection exists if and only if ran(r), the range of T, is located, in the sense that the distance