Spectral Methods For Operators of Mathematical Physics

The charm of Mathematical Physics resides in the conceptual difficulty of understanding why the language of Mathematics is so appropriate to formulate the laws of Physics and to make precise predictions. Citing Eugene Wigner, this "unreasonable appropriateness of Mathematics in the Natural Sciences" emerged soon at the beginning of the scientific thought and was splendidly depicted by the words of Galileo: "The grand book, the Universe, is written in the language of Mathematics." In this marriage, what Bertrand Russell called the supreme beauty, cold and austere, of Mathematics complements the supreme beauty, warm and engaging, of Physics.

Spectral theory of bounded linear operators teams up with von Neumann’s theory of unbounded operators in this monograph to provide a general framework for the study of stable methods for the evaluation of unbounded operators. An introductory chapter provides numerous illustrations of unbounded linear operators that arise in various inverse problems of mathematical physics.