A memorial conference for Leon Ehrenpreis was held at Temple University, November 15-16, 2010. In the spirit of Ehrenpreiss contribution to mathematics, the papers in this volume, written by prominent mathematicians, represent the wide breadth of subjects that Ehrenpreis traversed in his career, including partial differential equations, combinatorics, number theory, complex analysis and a bit of applied mathematics. With the exception of one survey article, the papers in this volume are all new results in the various fields in which Ehrenpreis worked .  There are papers in pure analysis, papers in number theory, papers in what may be called applied mathematics such as population biology and parallel refractors and papers in partial differential equations. The mature mathematician will find new mathematics and the advanced graduate student will find many new ideas to explore.A biographical sketch of Leon Ehrenpreis by his daughter, a professional journalist, enhances the memorial tribute and gives the reader a glimpse into the life and career of a great mathematician.

Preface. Biographical Sketch of Leon Ehrenpreis (Yael Ehrenpreis Meyer).- Differences of Partition Functions - The Anti-Telescoping Method(G.E. Andrews).- The Extremal Plurisubharmonic Function for Linear Growth (D. Bainbridge).- Mahonian Partition Identities Via Polyhedral Geometry (M. Beck, B. Braun, N. Le).- Second Order Modular Forms with Characters (T. Blann, N. Diamantis).- Disjointness of Moebius From Horocycle Flows (J. Bourgain, P. Sarnak, T. Zeigler).- Duality and Differential Operators for Harmonic MAASS Forms (K. Bringmann, B. Kane, R.C. Rhoades).- Function Theory Related to the Group PSL2(R) (R. Bruggeman, J. Lewis, D. Zagier).- Analysis of Degenerate Diffusion Operators Arising in Population Biology (C.L. Epstein, R. Mazzeo).- A Matrix Related to the Theorem of Fermat and the Goldbach Conjecture (H.M. Farkas).- Continuous Solutions of Linear Equations (C. Fefferman, J. Kollár).-

Recurrence for Stationary Group Actions (H. Furstenberg, E. Glasner).- On the HondaKaneko Congruences (P. Guerzhoy).- Some Intrinsic Constructions on Compact Riemann Surfaces (Robert C. Gunning).- The Parallel Refractor (C.E. Gutiérrez, F. Tournier).- On a Theorem of N. Katz and Bases in Irreducible Representations (D. Kazhdan).- Vector-valued Modular Forms with an Unnatural Boundary (M. Knopp, G. Mason).- Loss of Derivatives (J.J. Kohn).- On an Oscillatory Result for the Coefficients of General Dirichlet Series (W. Kohnen, W. de Azevedo Pribitkin).- Representation Varieties of Fucsian Groups (M. Larsen, Alexander Lubotzky).- Two Embedding Theorems (G.A. Mendoza).- Cubature Formulas and Discrete Fourier Transform on Compact Manifolds (I. Z. Pesenson, D. Geller).- The Moment Zeta Function and Applications (I. Rivin).- A Transcendence Criterion for CM on Some Families of CalabiYau Manifolds (P. Tretkoff).- Ehrenpreis and the Fundamental Principle (F. Treves).- Minimal EntireFunctions (B. Weiss).- A Conjecture by Leon Ehrenpreis about Zeroes of Exponential Polynomials (A. Yger).- The Discrete Analog of the MalgrangeEhrenpreis Theorem (D. Zeilberger).- The Legacy of Leon Ehrenpreis.- PhD Students.- Publications of Leon Ehrenpreis.