Ray Rosentrater

Ray Rosentrater

Professor of Mathematics
Phone: (805) 565-6185
Email: rosentr@westmont.edu
Office Location: Winter Hall 302

Office Hours
By appointment

Operator theory

Professor Rosentrater has taught at Westmont since 1980, and has won the Teacher of the Year Award and the Faculty Research Award. He held a Fulbright fellowship in 1995. He commutes about 10 miles one way by bicylcle almost daily to work.

Course web pages

Professor Rosentrater teaches

  • Calculus
  • Linear algebra
  • Discrete mathematics
  • Fundamentals of mathematics


  • Ph.D. in Mathematics, Indiana University
  • M.Sc. in Computer Science, University of Toronto
  • M.S. in Mathematics, Indiana University
  • B.A. in Mathematics, Messiah College

Research Interests

  • Operator theory

Selected Publications

  • "Representational Efficiency." Mathematics Magazine, 64 (2011), 185-195.
  • (with Jim Gleason) “Xia’s Analytic Model of a subnormal Operator and its Applications.” Rocky
    Mountain Journal of Mathematics. 38:3 (2008), 849-890.
  • (with Jim Gleason) “The Mosaic and Principal Function of a Subnormal Operator.” Integral Equations
    and Operator Theory, 55 (2006), 69-82.
  • “Another Stick-Breaking Game: Problem 11089.” The American Mathematical Monthly, 113 (2006),
  • “The Sample Correlation Coefficient from a Linear Algebra Perspective.” The College Mathematics
    Journal, 36 (2006), 47-50.