Philip T. Gressman
Department of Mathematics
University of Pennsylvania
David Rittenhouse Lab
209 South 33rd Street
Philadelphia PA 19104
Email:
Phone: (215) 898-7845
Office: DRL 3E5C
Office Hours Fall 2012
MATH 584: W 11:30-12:30, 2:00-2:30
MATH 241: T 2:15-3:00, Th 4:30-5:15
or by appointment
I am an Associate Professor in the Department of Mathematics at the Unversity of Pennsylvania. I am also affiliated with the Applied Mathematics and Computational Science (AMCS) program. My research interests lie at the intersection of harmonic analysis and geometry, including the study of geometric averaging operators (generalizing the Radon transform), oscillatory integral operators, sublevel set estimates, the Fourier restriction problem, and related objects and applications. Recently I have also worked on applications of harmonic analysis to PDEs, specifically the Boltzmann equation and the Gross-Pitaevskii Hierarchy. I am currently supported by an Alfred P. Sloan Reasearch Fellowship and NSF grant DMS-1101393.

In case you are nostalgic, my old webpage can be found here. The one before that is available here.

Research

Current CV (September 2012)
Recent Work and Links

Work In Progress

$L^p$-improving estimates for Radon-like transforms via multilinearization
On the uniqueness of solutions to the periodic 3D Gross-Pitaevskii hierarchy (w/ V. Sohinger and G. Staffilani)
A characterization of the restriction phenomenon in terms of convolutions of measures (w/ A. Iosevich)

Recent Papers Hosted at arXiv.org, MR citations provided when available

[1205.5774] Scalar oscillatory integrals in smooth spaces of homogeneous type
[1205.5773] Fractional Poincare and logarithmic Sobolev inequalities for measure spaces
[1202.4088] (w/ J. Krieger and R. M. Strain) A non-local inequality and global existence (MR2914961)
[1011.5441] (w/ R. M. Strain) Global Classical Solutions of the Boltzmann Equation without Angular Cut-off (MR2784329)
[1010.0661] Uniform sublevel Radon-like inequalities
[1007.1276] (w/ R. M. Strain) Sharp anisotropic ests. for the Boltzmann collision op. and its entropy production (MR2807092)
[0911.1283] On multilinear determinant functionals (MR2784813)
[0909.0875] Uniform geometric estimates for sublevel sets (MR2855039)
[0812.2589] $L^p$-improving estimates for averages on polynomial curves (MR2576685)
[0802.0428] Rank and regularity for averages over submanifolds (MR2541274)

Fall 2012 Courses

Math 241: Calculus IV Section 001. Sturm-Liouville problems, orthogonal functions, Fourier series, and partial differential equations including solutions of the wave, heat and Laplace equations, Fourier transforms. Introduction to complex analysis. Use of symbolic manipulation and graphics software.
Meets TTh 3:00-4:30 in DRL A2 with recitations on Wednesdays and Fridays at either 9 or 10. See the department calculus page for general information and the section 001 blackboard page for more details. Also don't forget about Piazza.

Math 584: Mathematics of Medical Imaging and Measurement. In the last 25 years there has been a revolution in image reconstruction techniques in fields from astrophysics to electron microscopy and most notably in medical imaging. In each of these fields one would like to have a precise picture of a 2 or 3 dimensional object which cannot be obtained directly. The data which is accessible is typically some collection of averages. The problem of image reconstruction is to build an object out of the averaged data and then estimate how close the reconstruction is to the actual object. In this course we introduce the mathematical techniques used to model measurements and reconstruct images. As a simple representative case we study transmission X-ray tomography (CT). In this context we cover the basic principles of mathematical analysis, the Fourier transform, interpolation and approximation of functions, sampling theory, digital filtering and noise analysis.
Meets TTh 12:00-1:30 in DRL 4C8. See the hand-out sheet. Students with limited programming experience should let me know.

Spring 2012 Courses

Math 240: Calculus III Section 002. Linear algebra: vectors, matrices, systems of linear equations, eigenvalues and eigenvectors. Vector calculus: functions of several variables, vector fields, line and surface integrals, Green's, Stokes' and divergence theorems. Series solutions of ordinary differential equations, Laplace transforms and systems of ordinary differential equations. Use of symbolic manipulation and graphics software.
Meets TTh 10:30-12:00 in Chem 102 with various Wednesday and Friday recitations. See the course description for full details. Homeworks will be posted weekly to blackboard.

Math 609/AMCS 609: Analysis. This semester we will cover various topics from measure theory, functional analysis and Fourier analysis as time permits. See the course description for a little more detail.
Meets TTh 3:00-4:30 in DRL 4C8. Weekly homework available on blackboard.

Teaching

Fall 2012
Spring 2012
Spherical Harmonics

Seminars and Colloquia

Analysis Seminar
AMCS Colloquium
All talks this week