Hello, my name is: Stephen C. Preston.
This is an old web site. I was a lecturer in the Mathematics Department at the University of Pennsylvania until 2005. I am now at the University of Colorado at Boulder.

---

Teaching:

• Fall 2002: Math 114 (Calculus II) and Math 360 (Advanced Calculus)
• Spring 2003: Math 170 (Mathematics and politics)
• Fall 2003: Math 104 (Calculus I) and Math 660 (Differential Geometry I)
• Spring 2004: Math 661 (Differential Geometry II)
• Fall 2004: Math 170 (Mathematics and politics) and Math 240 (Calculus III)
• Spring 2005: Math 241 (Calculus IV)

---

Extracurricular activities:
I was the faculty advisor for the math club, Pi Mu Epsilon.

---

Papers:

• `Eulerian and Lagrangian stability of fluid motions,' doctoral dissertation.
• `For ideal fluids, Eulerian and Lagrangian instabilities are equivalent,' GAFA, volume 14, no. 5.
• `Nonpositive curvature on the area-preserving diffeomorphism group,' J. Geom. Phys., volume 53, no. 2.
• `Singularities of the exponential map on the volume-preserving diffeomorphism group,' with David G. Ebin and Gerard Misiolek, to appear in GAFA.