am Dean of the College of Arts and
Sciences at Penn.
I am also Faculty Master of Riepe College House.
I am also the Robert A. Fox
Leadership Professor in the
School of Arts and Sciences, and a Professor of
Middle school math problem of the
you are a teacher and would like more information about these, please drop
me an email at email@example.com )
Mathematician Herb Wilf and
I collaborated on a junior/senior-level
textbook on Numerical Analysis using Maple.
My research interests are Partial Differential Equations and Differential
Recent preprints and publications:
- (with H. Gluck, R. Komendarczyk, P. Melvin, H. Nuchi,
C. Shonkwiler and D.S. Vela-Vick) "Generalized Gauss maps and integrals
for three-component links: Toward higher helicities for magnetic fields and
fluid flows, Part II"
Algebraic and Geometric Topology
13 (2013) 2897-2923
arXiv paper 1207.1793).
- (with H. Gluck, R. Komendarczyk, P. Melvin, C. Shonkwiler. and D.S.
Vela-Vick) "Generalized Gauss maps and integrals for three-component
links: Toward higher helicities for magnetic fields and fluid flows
J. Math. Phys. 54 (2013) 013515
ArXiv paper 1101.3374)
- (with H. GLuck and P. Storm) "Lipschitz minimality of Hopf fibrations
and Hopf vector fields"
Algebraic and Geometric Topology
13 (2013) 1369-1412
( ArXiv paper 1009.5439)
- (with H. Gluck) "Linking, twisting, writhing and helicity on the
3-sphere and in hyperbolic 3-space" J. Differential Geometry
94 (2013) 87-128.
( ArXiv paper 1009.3561)
- (with H. Gluck, R. Komendarczyk, P. Melvin, C. Shonkwiler and D.S.
Vela-Vick) "Triple linking numbers, ambiguous Hopf invariants and integral
formulas for three-component links" (ArXiv paper 0901.1612)
and in Mat. comtemp. 34 (2008) 251-283.
- (with H. Gluck) "Linking
integrals in the n-sphere" (ArXiv paper 0802.0320)
and in Mat. comtemp. 34 (2008) 233-250.
- (with H. Gluck) "Electrodynamics and the Gauss linking integral on
the 3-sphere and in hyperbolic 3-space" (ArXiv paper
0510388) and in the
Journal of Mathematical Physics vol 49, 023504 (2008)
- (with H. Gluck, D.
Pomerleano and D.S. Vick) "The Four-vertex
Theorem and its converse", Notices AMS 54 (2007) 192-207
0609268). A translation of this paper into Chinese appears in
Mathematics in Chinese Translation 27 (2009) 313-328.
- (with S. Cappell, H. Gluck and E. Miller) "Cohomology of harmonic
forms on Riemannian manifolds with boundary", Forum Math.
18 (2006) 923-931 ( PS version [137K], PDF version [119K], ArXiv paper
- (with H. Gluck) "The Gauss linking integral on the 3-sphere and in
hyperbolic 3-space" (ArXiv paper
- "Deforming metrics in the direction of their Ricci tensors (Improved
version)", in Collected Papers on Ricci Flow, HD Cao, B Chow, SC
Chu and ST Yau eds, Series in Geometry and Topology 37
(2003) 163-165, International Press. (PS
version (140KB), PDF version)
- (with J. Cantarella and H. Gluck) "Hodge decomposition of vector fields on
bounded domains in 3-space", American Mathematical Monthly 109
(2002), 409-442. (PDF version (2.6
- (with J. Cantarella and H. Gluck) "The Biot-Savart
application to knot theory, fluid dynamics and plasma physics", J.
Mathematical Physics 42 (2001) 876-905. ( PDF version (1.5MB))
- (with J. Cantarella and H. Gluck) "Upper Bounds for the Writhing of
Knots and the Helicity of Vector Fields", in
Knots, Braids, and Mapping Class Groups - Papers Dedicated to Joan S.
Birman, J. Gilman, X-S. Lin and W. Menasco (eds),
Studies in Advanced Mathematics AMS/International Press
Studies in Advanced Mathematics 24 (2001) 1-21. (PDF version (314KB), PS version (1.7MB))
- (with J. Cantarella, H. Gluck and M. Teytel) "Isoperimetric problems for the
helicity of vector fields and the Biot-Savart and curl operators" J.
Mathematical Physics 41 (2000) 5615-5641. (PDF version (1.3MB))
- (with J. Cantarella, H. Gluck and M. Teytel) "The spectrum of the curl
operator on spherically symmetric domains" Physics of Plasmas 7
(2000) 2766-2775 (PDF version (1.2MB))
- (with H. Goldschmidt)
"Metrics with Prescribed Ricci
Curvature of Constant Rank I. The Integrable Case", Advances in Mathematics
145, 1-97 (1999) (Postscript version
- (with J. Cantarella, H. Gluck and M. Teytel) "Influence of geometry
and topology on helicity", Magnetic Helicity in Space and Laboratory
Plasmas, M. Brown, R. Canfield and A. Pevtsove (eds), Geophysical
Monograph 111, American Geophysical Union (1999) 17-24. (PDF version (165KB), PS version (879KB))
- (with J. Cantarella and H. Gluck) "The spectrum of the curl operator
on the flat torus", preprint 35 pp.
- (with H.
Goldschmidt) "Aspects of prescribing Ricci curvature",
in CR Geometry and Overdetermined Systems, Advanced Studies in
Mathematics 25 (1997) 60-84.