Professor of Mathematics
University of Pennsylvania

CAGE (Combinatorics, Algebra, and Geometry) Seminar Webpage

Penn Online Seminar Listing for Upcoming and Past CAGE seminar talks

IPAC (Important Papers in Algebraic Combinatorics) Seminar

My research interests are in algebraic and enumerative combinatorics. In particular, I work on problems involving symmetric functions and Macdonald polynomials, combinatorial statistics and q-analogs, rook polynomials, and am also interested in the zeros of polynomials and analytic functions. I like experimental mathematics, and often use computer algebra packages such as Maple in my research, to develop and test conjectures.


  • Publications and Preprints,


  • The q,t-Catalan Numbers and the Space of Diagonal Harmonics in pdf format or ps format

    The official bound version of this book can be ordered from the AMS. It is part of the AMS University Lecture Series.


    Spring 2022

  • Math 581 (Topics in Combinatorial Theory)


  • PhD and Masters Students

  • Postdoctoral

    Upcoming Presentations and Conferences

  • GarsiaFest, La Jolla, CA June 17-20, 2019

  • University of Virginia Algebra Seminar, Friday, October 11, 2019.

  • Workshop on Unimodality, Log-concavity and beyond, March 16-20, 2020, Institut Mittag-Leffler, Djursholm, Sweden

  • Mini-Symposium on Emerging Connections in Symmetric Functions (co-organized with Andy Wilson), 2020 Conference on Discrete Mathematics, Portland, Oregon, June 3-4, 2020.

  • The 32st International Conference on Formal Power Series and Algebraic Combinatorics (FPSAC), Bar-llan University, Ramat-Gan, Israel, July 13-17, 2020.

    Some Past Workshops

  • BIRS Workshop on Applications of Macdonald Polynomials, September 9-14, 2007

  • MFO Workshop on Combinatorial Representation Theory, Oberwolfach, Germany, March 22-27, 2010

  • BIRS Workshop on Quasisymmetric Functions, November 14-19, 2010

  • MFO Workshop on Enumerative Combinatorics, Oberwolfach, Germany, March 2-8, 2014

  • MFO Workshop on Enumerative Combinatorics, Oberwolfach, Germany, May 13-19, 2018

  • BIRS Workshop on Hessenberg Varieties in Combinatorics, Geometry, and Representation Theory, Banff, CA Oct. 21-26, 2018

  • BIRS Workshop on Representation Theory Connections to (q,t)-Combinatorics, Banff, CA Jan. 20-25, 2019

    Transparencies from Selected Presentations

  • The (q,t)-Catalan Numbers and the Space of Diagonal Harmonics, hour long Invited Address, AMS Sectional, Orlando Fl. Nov. 9, 2002.

  • A Combinatorial Model for the Macdonald Polynomials (in pdf format), or postscript format, hour long presentation at the Workshop on Resolutions, Inverse Systems, and Coinvariants, University of Ottawa, Jan. 13, 2005.

  • Recent Combinatorial Results involving Macdonald Polynomials and Diagonal Harmonics (in postscript format), or pdf format, Plenary Address at the 18th International Conference on Formal Power Series and Algebraic Combinatorics (FPSAC '06), San Diego, CA, June 22, 2006.

  • The Monotone Column Permanent Conjecture and Multivariate Eulerian Polynomials , hour long presentation at the 26th Clemson mini-Conference on Discrete Mathematics and Algorithms, Clemson University, Oct. 28, 2011.

  • Three Faces of the Delta Conjecture , hour long presentation at the Triangle Lectures in Combinatorics, March 30, 2019, Wake Forest University

    The PhD Oral Exam in Combinatorics at Penn

    Editorial Boards

  • Transactions of the AMS

  • Journal of Combinatorics

  • Bulletin of Parana's Mathematical Society

  • Involve


  • Member of the AMS and MAA

  • Fellow of the AMS

    Department of Mathematics
    University of Pennsylvania
    209 South 33rd St.
    David Rittenhouse Laboratory
    Philadelphia, PA 19104-6395
    Phone: 215-573-9093
    Fax: 215-573-4063
    email: jhaglundATmath.upenn.edu