Sidney Martin Webster

Sidney Martin Webster (born 12 November 1945 in Danville, Illinois) is an American mathematician, specializing in multidimensional complex analysis.^[1]

After military service, Webster attended the University of California, Berkeley as an undergraduate and then as a graduate student, receiving a PhD in 1975 under the supervision of Shiing-Shen Chern^[1] with thesis Real hypersurfaces in complex space.^[2] Webster was a faculty member at Princeton University from 1975 to 1980 and at the University of Minnesota from 1980 to 1989. In 1989 he became a full professor at the University of Chicago. He has held visiting positions at the University of Wuppertal, Rice University, and ETH Zurich.^[1]

Webster was a Sloan Fellow for the academic year 1979–1980. In 1994 in Zurich he was an invited speaker of the International Congress of Mathematicians.^[3] In 2001 he received, jointly with László Lempert, the Stefan Bergman Prize from the American Mathematical Society.^[1] In 2012 Webster was elected a Fellow of the American Mathematical Society.

In 1977 he proved a significant theorem on biholomorphic mappings between algebraic real hypersurfaces.^[4] Using his expertise on Chern-Moser invariants, he developed a theory that provides a complete set of invariants for nondegenerate real hypersurfaces under volume-preserving biholomorphic transformations.^[5] He used the edge-of-the-wedge theorem to prove an extension theorem that generalized a 1974 theorem of Charles Fefferman.^[6][1]

Selected publications

• Webster, S. M. (1979). "The rigidity of C-R hypersurfaces in a sphere". Indiana University Mathematics Journal. 28 (3): 405–416. doi:10.1512/iumj.1979.28.28027. JSTOR 24892266.
• Webster, S. M. (1979). "Biholomorphic mappings and the Bergman kernel off the diagonal". Inventiones Mathematicae. 51 (2): 155–169. Bibcode:1979InMat..51..155W. doi:10.1007/BF01390226. S2CID 119485248.
• with Klas Diederich: Diederich, K.; Webster, S. M. (1980). "A reflection principle for degenerate real hypersurfaces". Duke Math. J. 47 (4): 835–843. doi:10.1215/S0012-7094-80-04749-3.
• with Jürgen K. Moser: Moser, Jürgen K.; Webster, Sidney M. (1983). "Normal forms for real surfaces in ${\displaystyle \mathbb {C} }$² near complex tangents and hyperbolic surface transformations". Acta Mathematica. 150: 255–296. doi:10.1007/BF02392973.