Operator Theory

This section provides a very brief and quick review of the basics of Hilbert space theory and functional analysis that are needed for this text. We list some of the most important notions and results that will be used throughout this book. It should be noted that the objective of this section is to merely refresh the memory rather than explain these concepts as they have been already explained in detail in volume 2 of this series [58]. The reader who did not study these concepts should consult introductory books on functional analysis for further details.