Ralph S. Phillips

Ralph Saul Phillips ( born June 23, 1913 in Oakland, California, † 23 November 1998) was an American mathematician who, among other things to dealt with Analysis.

Life and work

Phillips studied at the University of California, Los Angeles (Bachelor 1935) and in 1939 received his doctorate at the University of Michigan at Theophil Hildebrandt. 1938 to 1940 ( and 1950 /1) he was at the Institute for Advanced Study. After that, he was instructor at the University of Washington and Harvard University. During the Second World War, he led a group at the Radiation Laboratory of the Massachusetts Institute of Technology (MIT), which served especially the development of radar. After that, he was assistant professor at the Courant Institute of Mathematical Sciences of New York University, the University of Southern California and 1958 at the University of California, Los Angeles. In 1960 he went to Stanford University where he was a professor until his retirement.

Phillips was concerned with semigroups of linear operators in functional analysis (about which he wrote an authoritative book with Einar Hille ). With Peter Lax, he developed geometric methods for time-dependent solution of the wave equation in regions outside compact " obstacles " that is, the scattering theory, where they examined the connection to the poles of the S- matrix. With Lax and Peter Sarnak, he worked on the theory of automorphic forms, especially in the context of scattering theory on symmetric spaces. In a book published in 1976 with Lax he examined here also the spectrum of the Laplacian on such spaces and proved the Selberg trace formula -.

In 1954/55 and in 1974 he was Guggenheim Fellow. In 1997 he received for his life's work the Leroy P. Steele Prize. He was a passionate sailor ( his sailboat called " wave equation" ). In 1970 he was invited speaker at the International Congress of Mathematicians in Nice ( Scattering theory for hyperbolic systems) and in 1966 in Moscow ( Scattering Theory with Peter Lax ).

Among his doctoral students include Andrew Majda and Michael Reed.

Writings

  • H. James, N. Nichols (Editor) The Theory of Servomechanisms ( MIT Radiation Lab), McGraw Hill 1947
  • Einar Hille: Functional Analysis and Semi- Groups, AMS 1957
  • With Peter Lax: Scattering Theory, Academic Press 1967, 2nd edition 1989 ( with appendices by Cathleen Synge Morawetz and G. Schmidt)
  • With Peter Lax: Scattering theory for automorphic functions, Princeton University Press 1976
  • Reminiscences about the 1930s, Mathematical Intelligencer, Vol 16, 1994, p.6
671353
de